A novel 3D deformation measurement method under optical microscope for micro-scale bulge-test. (November 2017)

• Record Type: Journal Article
• Authors: Wu, Dan; Xie, Huimin
• Is Part Of: Optics and lasers in engineering. Volume 98(2017)
• Page Start: 190
• Page End: 197
• Publication Date: 2017-11
• Subjects: Micro-scale -- 3D deformation measurement -- Bulge-test -- Gratings -- Optical microscope; Lasers in engineering -- Periodicals; Optical measurements -- Periodicals; Optics -- Periodicals; Lasers en ingénierie -- Périodiques; Mesures optiques -- Périodiques; Optique -- Périodiques; 621.36605
• DOI: 10.1016/j.optlaseng.2017.07.001
• Languages: English
• ISSNs: 0143-8166

Abstract

Highlights: A micro-scale 3D deformation measurement method is proposed and applied for the measurement of bulge-test. The superiority of this method is insensitive to the image distortion and drifting of the microscope. The accuracy is estimated, and the out-of-plane displacement for the experiment (grating frequency is 80 lines/mm) in this paper is 0.18 µm. The accuracy can be improved by increasing the grating frequency. A thermal/mechanical coupling bulge-test apparatus was exploited. The proposed 3D deformation measurement method is applied to measure the bulge deflection of the thin films. The mechanical properties of the polyimide film is tested at room temperature and 150 °C. The elastic modulus of the polyimide film tested at 150 °C by the proposed method decrease 27% compared with that at room temperature (25 °C). Abstract: A micro-scale 3D deformation measurement method combined with optical microscope is proposed in this paper. The method is based on gratings and phase shifting algorithm. By recording the grating images before and after deformation from two symmetrical angles and calculating the phases of the grating patterns, the 3D deformation field of the specimen can be extracted from the phases of the grating patterns. The proposed method was applied to the micro-scale bulge test. A micro-scale thermal/mechanical coupling bulge-test apparatus matched with the super-depth microscope was exploited. With the gratings fabricated onto the film, the deformed morphology of the bulged film was measured reliably. The experimental results show that the proposed method and the exploited bulge-test apparatus can be used to characterize the thermal/mechanical properties of the films at micro-scale successfully.