Tham khảo tài liệu 'frontiers in guided wave optics and optoelectronics part 18', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Optical Beam Steering using a 2D MEMS Scanner 665 Fig. 2. Principle of operation of the MEMS scanner. By combining these basic displacements any point of the scanning area can be reached. Fig. 3. CAD image of the device showing the two pairs of electrostatic combdrive actuators the compliant suspension springs and the movable platform. the orthogonal direction by either compressing or extending the compliant beams displacement in Y . Fig. 2 shows the displacements along the two main axes X and Y . With combining these basic displacements by applying different signal amplitudes to combdrive actuators any off-axis points of the reachable area can be addressed. Once the desired position reached the movable platform can be locked in place by applying a voltage between the movable platform and the base of the chip Fig. 4 . Depending on the electrical current and the voltage applied the locking is either temporary or permanent. In case of a temporary locking the platform is held in place as long as the licking voltage is applied. For the permanent one the platform stays at the desired position even after all the voltages are set back to zero. 666 Frontiers in Guided Wave Optics and Optoelectronics The backside of the chip includes a through hole under the platform to accommodate the movable lens and transmit light across the MEMS chip. applying voltage to substrate Fig. 4. Locking mechanism principle. Device layer is pulled down to the handle by applying a voltage between these two layers. Depending on the voltage current applied the resulting locking mechanism can be either temporary or permanent. 3. Simulations Simulations were carried out to optimize the size and the shape of the compliant beams. By comparing straight and curved beams for a given deformation the maximal stress occurs in the same region of the beam but its value is different. In case of a straight beam a maximal stress of 160 MPa was obtained while the maximal stress of the curved beam was 110 MPa. The
