Abstract: Provided are a methods and systems for determining a topography of an object. In an embodiment, a system includes a reference probe configured to measure a surface of a reference surface and to generate a reference signal, a measuring probe configured to measure a surface of an object and to generate a measurement signal, a sensor configured to sense a position of the measuring probe and to generate a sensor signal, and a combiner configured to receive the sensor signal and the measurement signal and to generate a combination signal therefrom. A desired distance between the measuring probe and the object is substantially maintained by adjusting the position of the measuring probe based on the measurement signal. A topography of the object is determined based at least on a comparison of the reference signal and the combination signal.

Abstract: Provided are a methods and systems for determining a topography of an object. In an embodiment, a system includes a reference probe configured to measure a surface of a reference surface and to generate a reference signal, a measuring probe configured to measure a surface of an object and to generate a measurement signal, a sensor configured to sense a position of the measuring probe and to generate a sensor signal, and a combiner configured to receive the sensor signal and the measurement signal and to generate a combination signal therefrom. A desired distance between the measuring probe and the object is substantially maintained by adjusting the position of the measuring probe based on the measurement signal. A topography of the object is determined based at least on a comparison of the reference signal and the combination signal.

Abstract: Provided are a method and system for measuring a distance to an object. The system includes an air gauge configured to sense a distance to a surface of the object and a sensor configured to measure at least one from the group including (i) a relative position of the air gauge and (ii) a relative position of the surface of the object. Outputs of the air gauge and the sensor are combined to produce a combined air gauge reading.

Abstract: An apparatus and method for precisely detecting very small distances between a measurement probe and a surface, and more particularly to a proximity sensor using a constant gas flow and sensing a mass flow rate within a pneumatic bridge to detect very small distances. Within the apparatus the use of a flow restrictor and/or snubber made of porous material and/or a mass flow rate controller enables detection of very small distances in the nanometer to sub-nanometer range. A further embodiment wherein a measurement channel of a proximity sensor is connected to multiple measurement branches.

Abstract: An apparatus and method for precisely detecting very small distances between a measurement probe and a surface, and more particularly to a proximity sensor using a constant gas flow and sensing a mass flow rate within a pneumatic bridge to detect very small distances. Within the apparatus the use of a flow restrictor, and/or snubber made of porous material, and/or a mass flow rate controller enables detection of very small distances in the nanometer to sub-nanometer range. A further embodiment wherein a measurement channel of a proximity sensor is connected to multiple measurement branches.

Abstract: An apparatus and method for precisely detecting very small distances between a measurement probe and a surface, and more particularly to a proximity sensor using a constant gas flow and sensing a mass flow rate within a pneumatic bridge to detect very small distances. Within the apparatus the use of a flow restrictor and/or snubber made of porous material and/or a mass flow rate controller enables detection of very small distances in the nanometer to sub-nanometer range. A further embodiment wherein a measurement channel of a proximity sensor is connected to multiple measurement branches.