Electromagnetic actuator and manufacturing method therefor
AssigneeThe Nippon Signal Co., Ltd.
InventorNorihiro Asada
Life of this patent
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Abstract
A portion of a torsion bar (6) for axially supporting a movable plate (5) of a planar electromagnetic actuator, is made conducting by diffusing boron therein in a high concentration. An external power source can thus be electrically connected to a planar coil (7) via the torsion bar (6) itself. As a result, the possibility of disconnection faults in the electrical wiring due to back and forth twisting movement of the torsion bar is eliminated, thus improving the durability and reliability of the electromagnetic actuator.
Claims8
An electromagnetic actuator having a semiconductor substrate with a movable plate, and a torsion bar for axially supporting the movable plate so as to be swingable relative to the semiconductor substrate integrally formed therewith, and incorporating a drive coil provided on a peripheral edge portion of said movable plate, and magnetic field generating means for applying a static magnetic field to said drive coil, the construction being such that said movable plate is driven by a magnetic force produced by passing a current through said drive coil, characterized in that an impurity is diffused on at least one portion of said torsion bar to form a conducting region, and an external power source and the drive coil are electrically connected by this conducting region.
A method of manufacturing an electromagnetic actuator, said method comprising:
- a step of forming a movable plate which is axially supported on a semiconductor substrate so as to be swingable, by piercing the semiconductor substrate by anisotropic etching from a lower face to an upper face excluding a portion forming a torsion bar;
- a step of forming a drive coil on an upper face periphery of the movable plate;
- and a step of securing a magnetic field generating means for applying a static magnetic field to the drive coil;
- characterized in that the movable plate is formed by said anisotropic etching after forming on at least a part of a portion forming the torsion bar, a conducting region in which a P-type impurity is diffused in high concentration, and when the drive coil is formed, then at the same time electrode terminal portions are formed on opposite end portions of said conducting region for respectively connecting said conducting region to an external power supply side and to the drive coil side.
Dependencies are inferred from the claim text.