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Proceedings Paper

Electromechanically driven microchopper for integration in microspectrometers based on LIGA technology
Author(s): Peter Krippner; Juergen Mohr; Volker Saile
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Paper Abstract

In recent years, microspectrometers made by the LIGA technology for the visible wavelength range have found their way into the market. Opening the wide field of spectral analysis in the infrared range, the concept of a highly transmissive hollow waveguide has been demonstrated successfully. In combination with linear detector arrays, hollow waveguide microspectrometers can be combined into handheld infrared spectrometer systems. The only obstacle to a miniaturized system is the lack of miniaturized light modulators. To solve this problem, a miniaturized light modulator has been developed. It consists of an oscillating stop driven by an electromagnetic actuator. It is made out of permalloy by means of LIGA micromechanics. Its outer dimensions of approx. 3.0 X 3.2 mm2 and a structure height of 280 micrometer allow it to be integrated into the plane of the entrance slit of the microspectrometer of about 20 mm to 30 mm size. The spectrometer has alignment structures to ensure positioning of the oscillating stop close to the entrance slit. This simplifies assembly. The actuator is excited by an hybrid integrated coil fixed by springs snapping into place during assembly. The maximum supply voltage of 5V allows the chopper to be used in low-voltage spectrometer systems, especially in handheld systems. The highest modulation frequency is more than 1 kHz, which is sufficient to work with the lead salt detectors commonly used. In this frequency range, detector noise is greatly attenuated compared to continuous-light operation. The paper contains an outline of the concept of the whole microspectrometer system. Experimental results are discussed to demonstrate the performance of the system.

Paper Details

Date Published: 2 September 1999
PDF: 11 pages
Proc. SPIE 3878, Miniaturized Systems with Micro-Optics and MEMS, (2 September 1999); doi: 10.1117/12.361256
Show Author Affiliations
Peter Krippner, Univ. of Karlsruhe (Germany)
Juergen Mohr, Institut for Microstructure Technology (Germany)
Volker Saile, Institut for Microstructure Technology (Germany)

Published in SPIE Proceedings Vol. 3878:
Miniaturized Systems with Micro-Optics and MEMS
M. Edward Motamedi; Rolf Goering, Editor(s)

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