Ultraprecision machining techniques for the fabrication of freeform surfaces in highly integrated optical microsystems

Stoebenau, Sebastian; Sinzinger, Stefan

doi:10.1117/12.826538

Cited by 9 publications

(3 citation statements)

References 10 publications

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“…The technique was chosen due to their huge potential to generate freeform structures as well as microstructures with very low surface deviations [17][18][19][20]. The fabrication process itself was developed by a partner and consists of different milling and planing steps carried out in a NiP alloy substrate material.…”

Section: Generation Of Single Mastermentioning

confidence: 99%

Fabrication of microoptical freeform arrays on wafer level for imaging applications

et al. 2015

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Miniaturized imaging systems combining an ultra-compact form factor in combination with the ability of refocusing and depth imaging have gained much interest in the field of mobile imaging. Therefore, artificial compound eye cameras are an extremely promising approach for the realization of compact monolithic camera modules on wafer level. Up to now, their imaging performance was limited to low resolution in the range of VGA format according to fabrication constrains given by the established microoptical fabrication methods, namely the reflow of photoresist. In order to overcome these classical limitations, the use of refractive freeform arrays (RFFA) instead of conventional microlens arrays is inevitable. To enable high volume and cost efficient mass production of artificial compound eye cameras for mass markets like the consumer electronics industry, their fabrication on wafer level is essential, but has not been published up to now. We present a wafer level based process chain enabling the fabrication of these elements for the first time.

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Section: Generation Of Single Mastermentioning

confidence: 99%

Fabrication of microoptical freeform arrays on wafer level for imaging applications

et al. 2015

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“…Therefore, in recent years, different methods have been investigated for fabrication of optical freeform surfaces in order to obtain high quality components. These techniques include diamond micromilling (Brinksmeier and Autschbach 2004;Stoebenau and Sinzinger 2009), ultraprecision diamond turning Yi and Li 2005), diamond flycutting (Stoebenau and Sinzinger 2009) and ultraprecision grinding (Ligtena and van Venkatesh 1985). Diamond micromilling is an alternative to machining aspheric or complex lenses with small positive and negative curvatures.…”

Section: Introductionmentioning

confidence: 99%

Design and fabrication of a freeform microlens array for uniform beam shaping

2011

Microsyst Technol

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Freeform optics has become a practical solution to solving number of problems in modern optical design. In this paper, we proposed a fabrication method using the combination of ultraprecision diamond machining and microinjection molding to achieve high volume and low cost freeform microlens manufacturing. The freeform microlens array discussed in this research is capable of redistributing a collimated light into a pre determined, in this case, a uniform pattern. The optical design, slow tool servo diamond machining, microinjection molding process and optical measurement were discussed. The simple optical design provided a platform for freeform microlens calculation. Slow tool servo diamond broaching was selected to fabricate the mold insert. After the mold insert was fabricated, microinjection molding machine was utilized to replicate the optical geometry into plastic substrates. The freeform microlens array that was fabricated in this research could achieve light re-distribution at the target with approximately 80% uniformity. The research conducted in this paper can be readily implemented in optical industry.

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“…Different fabrication methods for microlens arrays have been developed in recent years. These methods include glass compression molding [2], diamond turning [3], diamond micromilling [4], diamond flycutting [5], and the thermal reflow method [6–8]. In 2006, a fast tool servo (FTS) was applied to the fabrication of microlens arrays [9].…”

Section: Introductionmentioning

confidence: 99%

Design, fabrication, and testing of a Shack–Hartmann sensor with an automatic registration feature

Zhou

Raasch

2016

Appl. Opt.

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In this research, design, construction, and testing of an innovative Shack–Hartmann sensor are described. As the most critical component, a polymer microlens array is injection molded and mounted on a board-level CMOS camera such that the focal plane of the microlens array is on the camera’s image plane. To allow for automatic registration of the spots of the measured area, a diffusing surface was created at the center of the lens array in the same diamond machining process in an uninterrupted operation. This unique diffusing surface does not generate an image spot. The no-spot feature functions as the reference in the measurement on the camera’s image plane. Using this unique feature, large global tip-tilt error can be detected and eliminated. In this research, both experiments and simulation have shown that the Shack–Hartmann sensor built using low cost components is capable of precision wavefront detection. This research also demonstrated that automatic registration based on the diffusing surface is simple and reliable.

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Ultraprecision machining techniques for the fabrication of freeform surfaces in highly integrated optical microsystems

Cited by 9 publications

References 10 publications

Fabrication of microoptical freeform arrays on wafer level for imaging applications

Fabrication of microoptical freeform arrays on wafer level for imaging applications

Design and fabrication of a freeform microlens array for uniform beam shaping

Design, fabrication, and testing of a Shack–Hartmann sensor with an automatic registration feature

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