Strain-based sensing of mirror position

摘要

Mechanical apparatus includes a base, a moving element, and a hinge, having a first end attached to the moving element. A supporting structure is attached to the base and to the second end of the hinge and has at least a component perpendicular to the hinge so as to translate rotation of the moving element about the hinge into elongation of the component, whereby the moving element rotates about the hinge relative to the base while the supporting structure is deformed as a result of the rotation of the moving element about the hinge. A strain-based rotation sensor is associated with the supporting structure and is configured to provide a signal indicative of the rotation of the moving element responsively to a strain induced due to deformation of the supporting structure as the result of the rotation of the moving element.

主权项

1. Mechanical apparatus, comprising:
a base; a moving element; a hinge, having a first end attached to the moving element and having a second end; a beam, which is perpendicular to the hinge and has ends that are attached to the base, wherein the second end of the hinge is attached to the beam at a location between the ends so that the beam elongates in response to rotation of the moving element about the hinge, whereby the moving element rotates about the hinge relative to the base while the beam is deformed as a result of the rotation of the moving element about the hinge; a strain-based rotation sensor, which comprises at least one cruciform doped region within the beam, the doped region comprising two pairs of mutually-perpendicular arms having respective resistances that vary responsively to a strain induced due to deformation of the beam as the result of the rotation of the moving element; and a sensing circuit, which is coupled to respective ends of the arms and is configured to output an indication of an angle of the rotation of the moving element responsively to the varying resistances.