Planar type mirror galvanometer incorpotating a displacement detection function
First Claim
1. A planar type mirror galvanometer incorporating a displacement detection function, comprising;
- a semiconductor substrate having a planar movable plate and a torsion bar formed integrally with the semiconductor substrate, the torsion bar supporting said movable plate about a torsion bar axis so that the movable plate is swingable about the axis, a planar coil for generating a magnetic field by means of an electric current for driving the movable plate, laid on an upper face peripheral edge portion of said movable plate, and a reflecting mirror provided on an upper face central portion which is surrounded by said planar coil, and magnets forming pairs with each other fixed to the semiconductor substrate so as to produce a magnetic field at the planar coil portions on the opposite sides of the movable plate which are parallel with the axis of the torsion bar, wherein a plurality of detection coils capable of electromagnetic coupling with said planar coil for detecting displacement of said movable plate are provided adjacent said movable plate and disposed at symmetrical locations with respect to said torsion bar, and a displacement detection current is superimposed on said electric current in the planar coil for driving the movable plate.
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Abstract
The present invention relates to a slim-type small size mirror galvanometer wherein the mirror displacement angle can be detected, made using semiconductor manufacturing techniques. Using semiconductor manufacturing techniques, a movable plate 5 and a torsion bar 6 for axially supporting the movable plate 5 are formed integrally on a silicon substrate 2, with a planar coil 7 and a total reflecting mirror 8 formed on an upper face of the movable plate 5, and permanent magnets 10A, 10B and 11A, 11B fixedly located so as to produce a magnetic field at the planar coil 7. The direction and quantity of current flowing in the planar coil 7 is controlled to variably control the swing angle of the movable plate 5 depending on the balance between the generated magnetic force and the torsion force in the torsion bar 6. Moreover, detection coils 12A, 12B are provided beneath the movable plate 5, and a detection current is superimposed on the drive current in the planar coil 7. The mirror displacement angle is detected by a change in the mutual inductance due to the detection current, between the planar coil and the detection coils 12A, 12B.
113 Citations
9 Claims
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1. A planar type mirror galvanometer incorporating a displacement detection function, comprising;
- a semiconductor substrate having a planar movable plate and a torsion bar formed integrally with the semiconductor substrate, the torsion bar supporting said movable plate about a torsion bar axis so that the movable plate is swingable about the axis, a planar coil for generating a magnetic field by means of an electric current for driving the movable plate, laid on an upper face peripheral edge portion of said movable plate, and a reflecting mirror provided on an upper face central portion which is surrounded by said planar coil, and magnets forming pairs with each other fixed to the semiconductor substrate so as to produce a magnetic field at the planar coil portions on the opposite sides of the movable plate which are parallel with the axis of the torsion bar, wherein a plurality of detection coils capable of electromagnetic coupling with said planar coil for detecting displacement of said movable plate are provided adjacent said movable plate and disposed at symmetrical locations with respect to said torsion bar, and a displacement detection current is superimposed on said electric current in the planar coil for driving the movable plate.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
Specification