本研究提出一個創新的高效能電磁式微致動器，此設計能夠以低驅動電流產生高磁通密度，並且具有位移量大與力量大以及低電磁干擾的特性。致動器是由電磁體與可動結構間隔28μm經過晶片接合而成的，而電磁體是以軟磁性材料Ni80Fe15Mo5薄殼包覆，這樣可以有效的降低漏磁，也就是能夠更有效的利用磁場，其中以有限元素法找出最佳的結構尺寸，另外也以數學解析的方式驗證此結構的特性。 此致動器的製作利用體型微加工技術與電鍍supermalloy (Ni80Fe15Mo5)合金，以Ni80Fe15Mo5製作磁性核，薄殼，可動板來取代傳統的permalloy (Ni80Fe20)。以奈米微壓痕儀測試由四根懸臂樑支撐的可動結構，其結構剛性為45μN/μm。當在平面線圈中通入293mA時，可以產生27.6μm的位移量，此時致動器所產生的力量為1240μN，與近幾年類似的致動器比較發現此致動器具有較低的驅動電流、較大的位移量與較大的力量。 A highly efficient electromagnetic microactuator that is capable of achieving large out-of-plane displacement and large force via passing through a small current density was designed and fabricated in this work. The actuator is assembled by one electromagnetic core (winded with copper coils) and a moving plate (supported with four suspended beams) with a spacing of 28μm. The electromagnet was packed in a Ni80Fe15Mo5 shell for diminishing the loss of magnetic flux. Finite element method was used to find out the possibly best design which is confirmed by theoretical analysis in magnetic paths. Bulk micromachining and electroplating of supermalloy (Ni80Fe15Mo5) were used in the fabrication of electromagnetic microactuator. Supermalloy was considered as the material of the electromagnetic core, shielding shell, moving plate with suspended beams rather than the conventional permalloy. The movable plate in the microactuator was tested with a nanoindenter. The stiffness is calculated to be 45μN/μm. Passing the current (with 293mA) through the copper coil of the electromagnet, the displacement of the moving plate, towards the electromagnet, measured by microtrak was 27.6μm. The exerted magnetic force is at 1240μN. These results show the microactuator with Ni80Fe15Mo5 alloy is efficient in producing large force and displacement.
