Abstract

Miniaturized FTIR spectrometer has been developed rapidly in recent years due to the increasing demands. MEMS micromirrors have been used to replace the movable mirror system, which is the largest part in conventional FTIRs. Electromagnetic actuators are suitable to drive the micromirrors because of their relatively large quasi-static translation range and high response speed. In addition, high surface quality is required for the micromirror. However, current MEMS based micromachining technologies cannot provide satisfactory surface quality. Therefore, a translation mircomirror with a large displacement, i.e., > 120 µm, and a novel magnetic field pulling-force assisted bonding technology are developed to bond a high surface quality (i.e., roughness of 2 nm and radius curvature over 15 m) mirror plate with a released microactuator using an adhesive. However, the touching points between the moving film and the substrate lead to a large starting position variation and low repeatability in operation. To solve these limitations, a repulsive force based translation micromirror utilizes a novel driving mechanism, i.e., permanent magnet ring above and electromagnet underneath the moving film, to lift and push the moving film away from the substrate for translation. As a result, the starting position of the repulsive force translating mirror is consistent and the repeatability is <1%. A maximum displacement of 144 µm can be achieved when a 140 mA current is applied. To eliminate the tilt of the translation micromirror during motion, a compensation system is developed which includes the translation mirror, a correcting mirror and a reflecting mirror. The correcting micromirror corrects the tilt by rotating the same angle as the translation micromirror with its rotating axis parallel to the tilting axis. The tilt of the attractive force translation micromirror can be reduced to 0.026° after compensation, so it can be used as a movable mirror in FTIRs to measure half of the midinfrared region between 13.6 µm an 25 µm. Therefore, the electromagnetic actuator based translation micromirror with large displacement, high surface quality can be successfully used as the movable mirror in the miniaturized FTIRs with the tilt compensation system.

Highlights

  • 1.1 Optical spectrum and spectrometerThe optical spectrum is a part of the electromagnetic spectrum

  • 6.1 Conclusions and contributions An electromagnetic actuator based translation micromirror has been successfully developed in this thesis to be used in a miniaturized FTIRs

  • The cost and size of the micromirror is significantly reduced by compared with the movable mirror in the conventional FTIRs

Read more

Summary

Introduction

1.1 Optical spectrum and spectrometerThe optical spectrum is a part of the electromagnetic spectrum. The study of optical spectrum started in the 17th century when Isaac Newton observed the phenomenon that a series of colors ranging from red to purple are generated after the natural light was dispersed by a prism. The optical spectrum is based on the theory that when light is projected to a matter, the atom of the matter absorbs the corresponding energy from the light, which leads to the change of light’s wavelength. Spectrometer, or spectrograph, is the device to record the intensity of the light passing through a sample and obtain the spectrum. The components of the sample are determined by using spectrum analysis. As an important optical instrument, spectrometer has been widely employed in various fields including agriculture, food safety, biology, medicine, petrochemistry, astronomy and the environment

Objectives
Methods
Findings
Conclusion

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.