Chromatic confocal matrix sensor with actuated pinhole arrays

Hillenbrand, Matthias; Weiss, Robert E.; Endrödy, Csaba; Grewe, Adrian; Hoffmann, Martin; Sinzinger, Stefan

doi:10.1364/ao.54.004927

Cited by 29 publications

(7 citation statements)

References 34 publications

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“…They are of fundamental importance in the realising of novel beam-shaping and -guiding concepts for ultra-compact and powerful optical units for micro-and nanostructuring, which will be integrated into the NPMM in the framework of our research work. Innovative microtechnical methods and procedures can be combined to build efficient active optical modules which will offer high potential for future applications [69][70][71].…”

Section: Future Workmentioning

confidence: 99%

Towards alternative 3D nanofabrication in macroscopic working volumes

Kühnel

Fröhlich

Füßl

et al. 2018

Meas. Sci. Technol.

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This paper gives an overview of the research carried out at TU Ilmenau towards the development and application of tip- and laser-based nanofabrication on flat and curved surfaces in extended macroscopic working areas. It is shown that sub-10 nm structures can be fabricated by scanning probe lithography (SPL). The use of soft stamps has revealed their suitability for nanoimprinting on curved surfaces. Laser-based methods for a maskless exposure of resist on curved surfaces utilising 405 nm laser diodes have already been tested successfully. Furthermore, the current work deals with two-photon polymerisation, which has great potential with regard to the fabrication of sub-wavelength structures. At present, the methods mentioned have all been applied only in working ranges <100 × 100 μm2 in the plane and <10 μm in height. To overcome these limitations, the nanofabrication techniques are now being integrated in the nanopositioning and measuring machines (NPMMs) developed at TU Ilmenau. They offer working volumes of up to 200 × 200 × 25 mm3 with a positioning resolution of 20 pm. To provide access to any geometry elements in the 3D space with nanometre precision, the machine concepts as well as the metrological concepts are further developed. Due to the increased demands of lowest trajectory deviations within the fabrication process, new real-time controllers for probing and fabrication systems are investigated, as well as interactions in combined force and positioning sensors. Further important research is carried out into interference lithography, to enable an exposure of non-planar substrates and to improve the lateral structure resolution at the same time. A mix-and-match combination of such methods that allows the simultaneous exposure of large substrate regions with nanofabrication methods such as SPL becomes possible on the basis of the NPMMs, and is another area of great potential with regard to the research work presented in this paper.

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Section: Future Workmentioning

confidence: 99%

Towards alternative 3D nanofabrication in macroscopic working volumes

Kühnel

Fröhlich

Füßl

et al. 2018

Meas. Sci. Technol.

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“…Utilizing a combination of pinhole arrays, 17 , 18 micro-lens arrays (MLAs), 18 – 20 and multi spectral cameras 21 or multi-point spectrometers, various approaches have shown the viability of extended field of view chromatic confocal metrology.…”

Section: Introductionmentioning

confidence: 99%

Toward areal chromatic confocal metrology

2023

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Chromatic confocal metrology suffers from a limitation in the number of measurement points that can be measured simultaneously in a single frame acquisition. We propose chromatic confocal areal metrology (ChromaCAM), in which the surface height for each point in a 2D grid of measurement spots, generated by a rectangular micro-lens array, is parallely analyzed through the utilization of a pinhole multiplexer unit, an analog optical analysis unit, and postprocessing algorithms. An experiment shows the viability of the simultaneous acquisition of multiple measurement points and the advantages over exisiting areal chromatic confocal approaches. Compared with conventional chromatic confocal metrology, the increase in the acquisition rate is significant and enables one-shot measurements.

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“…For efficiency improvement, efforts have been focused on lateral scanning mechanisms. In 2015, Hillenbrand M et al [11] presented a chromatic confocal matrix sensor with actuated pinhole arrays for 3D object snapshot acquisition, which significantly improved the lateral resolution by applying pinhole arrays. In 2020, Luo D et al [12] proposed a direct area scanning method for 3D surface profilometry based on a tilted focal field.…”

Section: Introductionmentioning

confidence: 99%

Thickness Measurement for Glass Slides Based on Chromatic Confocal Microscopy with Inclined Illumination

Zhang

Shang

et al. 2021

Photonics

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Chromatic confocal microscopy is a widely used method to measure the thickness of transparent specimens. In conventional configurations, both the illumination and imaging axes are perpendicular to the test specimen. The reflection will be very weak when measuring high-transparency specimens. In order to overcome this limitation, a special chromatic confocal measuring system was developed based on inclined illumination. This design was able to significantly improve the signal-to-noise ratio. Compared with conventional designs, the proposed system was also featured by its biaxial optical scheme, instead of a coaxial one. This biaxial design improved the flexibility of the system and also increased the energy efficiency by avoiding light beam splitting. Based on this design, a prototype was built by the authors’ team. In this paper, the theoretical model of this specially designed chromatic confocal system is analyzed, and the calculating formula for the thickness of transparent specimen is provided accordingly. In order to verify its measurement performance, two experimental methodology and results are presented. The experimental results show that the repeatability is better than 0.54 μm, and the axial measurement accuracy of the system could reach the micron level.

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Chromatic confocal matrix sensor with actuated pinhole arrays

Cited by 29 publications

References 34 publications

Towards alternative 3D nanofabrication in macroscopic working volumes

Towards alternative 3D nanofabrication in macroscopic working volumes

Toward areal chromatic confocal metrology

Thickness Measurement for Glass Slides Based on Chromatic Confocal Microscopy with Inclined Illumination

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