High-resolution micro-optical accelerometer with an electromagnetic driver: design and analysis

Abstract

Optical displacement detection is widely used in various micro-electro-mechanical system (MEMS) sensors because of its high sensitivity. The optical accelerometer has a high theoretical resolution. However, due to the small working range of optical detection, the open-loop measuring range of a high-resolution optical accelerometer is usually only tens to hundreds of milligrams. To increase the measurement range, we propose a high-resolution micro-optical accelerometer with electromagnetic force feedback. The optical principle, mechanical structure, and manufacturing process are analyzed. The accelerometer is predicted to work in the first modal with displacement sensitivity at 2.56 µm/g, corresponding to 0th diffraction beam optical sensitivity 1.93%/nm. The designed electromagnetic driver can increase the acceleration measurement range from 0.012 to ± 20 g . These results provide a theoretical basis for the design and fabrication of a high-resolution micro-optical accelerometer with an electromagnetic driver. The electromagnetic drive scheme introduced effectively improves the dynamic range of high-precision optical accelerometers and can be applied to other optical MEMS sensors.

Optical Interferometric MEMS Accelerometers

“…increase the range from 0.012 g to ±20 g. [121] Later, Gao et al designed the driving coil on the mass to form a force feedback with the micro-magnet on the glass substrate (Figure 31d). [122] Williams et al used large-scale motor coils instead of microcoils to form an electromagnetic force feedback accelerometer, as shown in Figure 31e, which reduced the difficulty of the process and ensured the uniformity of the magnetic force distribution.…”

“…To better extend the working range, Gao et al. processed the micro coil on the surface of the glass substrate and formed a force feedback system with the micromagnet (Figure 31c), which can increase the range from 0.012 g to ±20 g. [ 121 ] Later, Gao et al. designed the driving coil on the mass to form a force feedback with the micro‐magnet on the glass substrate (Figure 31d).…”

“…Reproduced with permission. [ 121 ] Copyright 2021, Optica Publishing Group. d) Coil machining in mass.…”

A Grating Interferometric Acoustic Sensor Based on a Flexible Polymer Diaphragm

“…The cavity gap usually has a machining error during the fabrication of the sensor [ 14 , 19 , 32 ]. Thus, the initial operating point is uncertain.…”

“…Therefore, a thinner metal reflector should be used while ensuring that the diaphragm has a certain optical reflectivity. The cavity gap usually has a machining error during the fabrication of the sensor [14,19,32]. Thus, the initial operating point is uncertain.…”