Systems and methods for non-invasive testing of electromechanical systems devices
AssigneeQUALCOMM MEMS Technologies, Inc.
InventorsWilhelmus A. De Groot, Daniel Felnhofer
Life of this patent
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Abstract
This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for testing an electromechanical systems (EMS) device. In one aspect, a laser is directed at a driven EMS device, and the reflected light pattern is analyzed to provide information regarding the characteristics of the driven EMS device. In some aspects, the reflected light pattern is analyzed to determine a resonant frequency of the EMS device or the damping forces acting on the EMS device. The resonant frequency can then be used to determine stresses within the EMS device, or pressure or temperature within a device package encapsulating the EMS device.
Claims30
A testing apparatus for measuring the resonant frequency of an electromechanical systems (EMS) device, the apparatus comprising:
- a laser emitting device configured to emit a laser beam;
- a first beam directing optic configured to redirect the laser beam towards an EMS device;
- a first focusing optic configured to focus the laser beam onto the EMS device;
- a second beam directing optic configured to redirect a light pattern reflected from the EMS device;
- and
- a light detection sensor configured to sense the reflected light pattern.
A testing apparatus for measuring the resonant frequency of an electromechanical systems (EMS) device, the apparatus comprising:
- a laser emitting device configured to emit a laser beam;
- a first beam directing optic configured to redirect the laser beam towards an EMS device;
- a first focusing optic configured to focus the laser beam onto the EMS device;
- a second beam directing optic configured to redirect a light pattern reflected from the EMS device;
- and
- means for sensing the reflected light pattern.
A method of testing an electromechanical systems (EMS) device to determine a resonant frequency of the EMS device, the method comprising:
- directing a laser beam at an EMS device;
- driving the EMS device with a periodic electrical signal to cause movement of at least one portion of the EMS device relative to other portions of the EMS device;
- varying the frequency of the periodic electrical signal;
- and
- analyzing a plurality of light patterns reflected from the EMS device when driven at a plurality of driving frequencies to determine a resonant frequency of the EMS device.
Dependencies are inferred from the claim text.