Measuring Probe Shielding for Thin Layer Thickness
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Solution Overview
Problem
Existing measuring probes face challenges in achieving high accuracy and sensitivity for measuring the thickness of thin layers due to geometric disturbances and the need for smaller, lighter designs that minimize interference with the measurement surface, while also being capable of using both magneto-inductive and eddy current methods without mutual interference.
Innovation Solution
A measuring probe design featuring a first coil device with a disk-shaped or ring-shaped carrier containing an Archimedean coil, along with a shield made of ferritic material, allows for spatial proximity of both coil devices, enhancing measurement sensitivity and accuracy by directing magnetic fields directly to the measurement surface, and using a soft magnetic contact cap and hard metal coating for improved wear resistance and shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If both first coil device (magnetic inductive) and second coil device (eddy current) are positioned close to each other to improve measurement sensitivity, then measurement accuracy is improved, but mutual interference between the two coil devices occurs
Solution Approach 1:
A shield made of ferritic material is positioned between the first coil device and the second coil device to act as an intermediary element. This shield blocks the magnetic field lines from one coil device from reaching the other, thereby preventing mutual interference while allowing both coil devices to be positioned close to each other for high measurement sensitivity
2Ease of operation
If the probe is made smaller and lighter to reduce geometric disturbances and minimize impact on measuring surface, then ease of operation is improved, but measurement sensitivity may be reduced
Solution Approach 1:
The first coil device and second coil device are arranged in a nested or closely integrated configuration within the probe housing, with the shield positioned between them. This compact arrangement allows the probe to be small and lightweight for easy operation while maintaining the close proximity of coil devices to the measuring surface for high sensitivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables high-resolution measurements of thin layers with improved sensitivity and accuracy, achieving single-digit nanometer resolution and effective curvature compensation, while maintaining a compact and non-intrusive probe design.
Implementation Method 1
the first coil device (44) comprises a first and a second coil (70, 71) and is designed for performing a magnetic inductive measurement method
Implementation Method 2
the second coil device (48) consists of a disk- or ring-shaped carrier (49) with at least one Archimedean coil (50, 51) and is designed for performing a measurement method using the eddy current method
Implementation Method 3
in particular made of a ferritic material, is provided between the first and second coil devices
Implementation Method 4
The mounting cap, designed to better guide the magnetic field lines to the measurement surface during magnetic inductive measurement, is preferably made of a soft magnetic material
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a measuring probe for measuring the thickness of thin layers, comprising a housing (14) and at least one sensor element (17) which is accommodated so as to be at least slightly movable along a longitudinal axis (16) and which comprises at least one first coil device (44) that includes a magnetic cup-type core (41) arranged along the longitudinal axis (16) of the housing (14). A first and a second coil (70, 71) are associated with the central pin (42) of the sensor element (17). The measuring probe further comprises a spherical positioning cap (21) which points in the direction of the surface to be measured of a device under test and has a contact surface (57) to be positioned on a surface to be measured. A second coil device (48) that is formed of a disk-shaped or ring-shaped support (49) having at least one Archimedean coil (51) is associated with the spherical positioning cap (21). Furthermore, a shield (83, 85) is provided at least in part between the first and the second coil device (44, 48).