Kazuya Matsumoto

A durable, shock-resistant electromagnetic optical scanner with polyimide-based hinges

This paper presents a moving-coil electromagnetic optical scanner with newly developed hinge structure consisting of multilayered polyimide films with aluminum lead wires in between. The main purpose is to obtain a scanner with good durability and shock resistance for practical use. Polyimide has both features, and the aluminum lead wires, connecting the moving-coils and fixed electrode pads, are more reliable, because they are located inside the hinge, where the stress caused by torsional deformation and atmospheric degradation are minimal. An electromagnetic actuator is used to satisfy the following requirements; a millimeter-sized mirror, resonant and galvanometric operation, and scan angle control. Scanner prototypes with two different specifications (i.e., fast scanner and slow scanner) were fabricated and characterized. Driven with a sinusoidal current of /spl plusmn/20 mA, the fast scanner and the slow one vibrated with an optical scan angle (/spl theta//sub o/) of 1/spl deg/ at the resonant frequency (f/sub r/) of 1.7 kHz and /spl theta//sub o/ of 60/spl deg/ at f/sub r/ of 72 Hz, respectively. Durability was demonstrated with a shock test of 2500 G and a life test of over 13 000 h. By substituting sputtered aluminum driving coil with electroplated copper coil, improved /spl theta//sub o/ of 16.8/spl deg/ was obtained at f/sub r/ of 2.7 kHz.

A Study on Nonlinear Torsional Characteristics of Polyimide Hinges

This paper reports our study results on nonlinear torsional characteristics of polyimide hinges. The purpose is to design hinge geometry appropriately so that undesirable vibrational characteristics cause by nonlinearity is minimized. Experimental result showed that widening the hinge causes significant nonlinearity, and it was verified by finite element analysis (FEA) without considering material nonlinearity. Dynamic characterization was performed using an optical scanner prototype having nonlinear hinges. The result showed good agreement with that by calculation. Appropriate hinge design has become possible since it can predict both static and dynamic characteristics can be predicted.