An apparatus, system, and method for managing an electrostatic charge of a workpiece are disclosed. The method comprises coupling an electrostatic voltmeter to a conductor, coupling a charge-adjustment system to the conductor, and coupling the conductor to the workpiece. A level of charge in the workpiece is adjusted, via the conductor, with the charge-adjustment circuit and a voltage of the workpiece is monitored, via the conductor, with the electrostatic voltmeter. A controller may be used to adjust the charge on the workpiece based upon the monitored voltage.

Apparatus and methods for interfacing with a micro-electromechanical system (MEMS) sensor are provided. In an example, an apparatus can interface circuit including an integrator circuit, a sample switch circuit, a saturation detector and a controller. The saturation detector can be configured to receive a signal indicative of an integration of charge of the sensor, to compare the signal indicative of the integration of charge to an integrator saturation threshold and to modulate a divide parameter using the comparison of the signal indicative of the integration of charge and the integrator saturation threshold. The controller can be configured to receive a clock signal and to control the sample switch circuit based on a phase of the clock signal and the divide parameter.

The invention relates to methods and apparatus for determining properties of a surface. Embodiments disclosed include an apparatus for measuring a surface charge of a sample, comprising: a sample holder having an opposed pair of electrodes and configured to hold a sample in position in a measurement volume between the electrodes such that a planar surface of the sample is aligned orthogonal to the electrode surfaces; a measurement chamber for containing a measurement liquid and having an open end configured to receive the sample holder to position the electrodes in a preset orientation; a laser light source positioned and configured to direct a laser beam through the measurement chamber between the electrodes and parallel to the planar surface of the sample when the sample holder is received in the measurement chamber; and a detector positioned and configured to detect scattered light from the measurement volume, wherein the apparatus is configured to allow for detection of the scattered light by the detector over a range of distances from the surface of the sample.

The invention relates to methods and apparatus for determining properties of a surface. Embodiments disclosed include an apparatus for measuring a surface charge of a sample, comprising: a sample holder having an opposed pair of electrodes and configured to hold a sample in position in a measurement volume between the electrodes such that a planar surface of the sample is aligned orthogonal to the electrode surfaces; a measurement chamber for containing a measurement liquid and having an open end configured to receive the sample holder to position the electrodes in a preset orientation; a laser light source positioned and configured to direct a laser beam through the measurement chamber between the electrodes and parallel to the planar surface of the sample when the sample holder is received in the measurement chamber; and a detector positioned and configured to detect scattered light from the measurement volume, wherein the apparatus is configured to allow for detection of the scattered light by the detector over a range of distances from the surface of the sample.

An electric field sensor having at least a first and second electrically conductive generally planar electrodes that are spaced apart from each other. A circuit is electrically connected to the electrodes which is configured to generate an output signal proportional to a time derivative of a varying electric field surrounding the electrodes. Optionally, three sets of spaced apart electrodes which are arranged perpendicularly relative to each other are used for three-dimensional measurements of the electric field.

The disclosure relates to a method for detecting surface electric field distribution of nanostructures. The method includes the following steps of: providing a sample located on an insulated surface of a substrate; spraying first charged nanoparticles to the insulated surface; and blowing vapor to the insulated surface to observe a distribution of the first charged nanoparticles via an optical microscope.

An apparatus comprises a comparator that includes a first input, a second input and an output. The comparator is configured for measuring a difference in voltage between a source coupled to the first input and another source coupled to the second input, and providing information associated with the measured difference at the output. The apparatus also comprises a controllable current source coupled to the first input of the comparator and configured for supplying or drawing current. The apparatus also comprises a digital logic circuit that is configured for controlling an amount of current supplied or drawn by the controllable current source. The apparatus is configured for measuring a charge associated with an external source that is coupled to the first input of the comparator.

An apparatus comprises a comparator that includes a first input, a second input and an output. The comparator is configured for measuring a difference in voltage between a source coupled to the first input and another source coupled to the second input, and providing information associated with the measured difference at the output. The apparatus also comprises a controllable current source coupled to the first input of the comparator and configured for supplying or drawing current. The apparatus also comprises a digital logic circuit that is configured for controlling an amount of current supplied or drawn by the controllable current source. The apparatus is configured for measuring a charge associated with an external source that is coupled to the first input of the comparator.

The present disclosure is directed to a device that provides high impedance contact pads for an electrostatic charge sensor. The contact pads are shared between the electrostatic charge sensor and drivers. The contact pads are set to a high impedance state by reducing current leakage through the drivers. Compared to electrostatic charge sensor with low impedance contact pads, the electrostatic charge sensor disclosed herein has high sensitivity, and is able to detect weak electrostatic fields.

The present disclosure is directed to a device that provides high impedance contact pads for an electrostatic charge sensor. The contact pads are shared between the electrostatic charge sensor and drivers. The contact pads are set to a high impedance state by reducing current leakage through the drivers. Compared to electrostatic charge sensor with low impedance contact pads, the electrostatic charge sensor disclosed herein has high sensitivity, and is able to detect weak electrostatic fields.