Chromatic Confocal Sensor Dual Waveguide Resolution Signal Trade-off
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Solution Overview
Problem
Chromatic-confocal measuring devices face a trade-off between resolution and signal strength, limiting their ability to accurately measure thin layers and surfaces with poor reflectivity or partially absorbing layers, as the achievable resolution is inversely dependent on the aperture size and signal intensity.
Innovation Solution
The use of multiple optical waveguides with different diameters, where a smaller diameter waveguide provides better resolution and a larger diameter waveguide carries more light, allowing for simultaneous measurement of objects with varying requirements for resolution and signal strength, with light sources operated alternately to maximize signal intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a smaller aperture is used, then measurement resolution is improved, but signal intensity deteriorates
Solution Approach 1:
The invention divides the single optical waveguide into multiple parallel optical waveguides with different diameters. Each waveguide acts as an independent channel with its own confocal aperture, allowing simultaneous acquisition of signals with different resolutions and intensities. The smaller waveguides provide high-resolution measurements while larger waveguides provide strong signal acquisition, resolving the contradiction between resolution and signal intensity.
2Device complexity
If a single optical waveguide configuration is used, then device complexity is reduced, but adaptability to different measurement requirements deteriorates
Solution Approach 1:
The invention creates a multi-functional measurement system where multiple optical waveguides with different diameters are integrated into a single device. Each waveguide serves multiple purposes: smaller waveguides optimize for high-resolution measurements of thin layers, while larger waveguides optimize for measurements of surfaces with poor reflectivity. This universal design allows the single device to adapt to various measurement requirements without needing separate specialized instruments.
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 approach enables improved resolution and signal strength, allowing for precise measurement of thin layers and surfaces with poor reflectivity, by utilizing the higher intensity of the larger waveguide when resolution is insufficient and the better resolution of the smaller waveguide when signal strength is inadequate.
Implementation Method 1
a first optical waveguide (26) whose end (29) forms a first confocal aperture (29)... a second optical waveguide (28) whose diameter is larger than the diameter of the first optical waveguide (26) and which is routed parallel to the first optical waveguide (26). The end of the second optical waveguide (28) represents a second confocal aperture (30)
Implementation Method 2
imaging optics (31) which are suitable for causing a chromatic focus shift of the measurement light and imaging the first confocal aperture (29) in a measurement area (34). Different wavelengths are thus focused at different heights.
Implementation Method 3
a first light source (21) which emits polychromatic measurement light... The light sources are each operated at time intervals, with the first light source (21) and the second light source (22) not being switched on at the same time
Data Source
Figure 1~2
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AI summary
The invention relates to an optical measuring device for measuring distances and/or thicknesses of a measurement object (34). A first light source (21) emits polychromatic measuring light, which passes through a first optical waveguide (26, 51) whose end forms a first confocal aperture (29, 53). Imaging optics (31) focus the first confocal aperture (29, 53) into a measurement area, with different wavelengths focused at different heights. Measuring light reflected from the measurement object (34) is focused back onto the first confocal aperture (29). A receiving and evaluation unit (39) measures the intensity of the measuring light reflected from the measurement object (34) and back through the first confocal aperture (29) as a function of wavelength and determines distances and/or thicknesses from this.According to the invention, the measuring device comprises a second optical waveguide (28, 52) which is guided parallel to the first optical waveguide (26, 51) and whose end forms a second confocal aperture (30, 54), wherein the diameter of the second optical waveguide (28, 52) is larger than the diameter of the first optical waveguide (26, 51). The receiving and evaluation unit (39) also measures the intensity of the measuring light reflected by the object being measured (34) and returning through the second confocal aperture (30, 54) as a function of the wavelength and determines distances and/or thicknesses from this.