A miniature eddy current sensor based on double coils

Abstract

The invention provides a miniature eddy current sensor based on double coils. The sensor comprises electrodes, an exciting coil, an induction coil, polyimide, through holes, a glass substrate and connecting lines, wherein the induction coil is arranged right above the exciting coil; the through holes are arranged in the center of the exciting coil and the center of the induction coil respectively and are used for connecting the electrode and the exciting coil as well as the electrode and the induction coil; the polyimide is used for insulation and support of the exciting coil and the induction coil; the glass substrate is arranged to the bottommost place; and the connecting lines are used for connecting the through holes and the electrodes. The sensor effectively detects the distance between the sensor and a metal object by utilizing the eddy current detection principle and combining the Faraday's law of electromagnetic induction. The miniature eddy current sensor overcomes the defect that a conventional eddy current sensor can be used with a signal conversion circuit being combined, thereby simplifying the detection system; and meanwhile, processing and manufacturing of the sensor are realized through micromachining process, so that the sensor is small in size, low in power consumption and easy to realize batch integration manufacture.

Description

Technical field [0001] The invention relates to an eddy current sensor, in particular to a novel miniature eddy current sensor based on a double coil structure. Background technique [0002] The eddy current sensor is a sensor based on the principle of the eddy current effect. It is a non-contact measurement sensor with superior performance and a non-destructive detection sensor. Eddy current sensors can be used to measure physical quantities such as distance, thickness, strain, and hardness, as well as vibration, rotation speed, temperature, speed, acceleration, etc., and therefore have a wide range of applications in the field of industrial production. [0003] The structure of the existing eddy current sensor is a single coil. During detection, an alternating current is applied to the coil to generate a primary magnetic field. When the detection object approaches the coil, an eddy current will be generated on the surface of the detection object according to Faraday’s law of elec...

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Problems solved by technology

However, the sensor designed in this patent is manufactured in a traditional manufacturing method, with a wire diameter of 0.29 mm. The entire sensor is relatively large in size, and the excitation coil and induction coil are located on both sides of the detection object during detection, so the detection range is limited by the structure of the sensor itself. limit

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