Actuator for micro-electromechanical system fabry-perot filter
View Patent ↗According to one embodiment, a micro-electrical mechanical system apparatus includes a bi-stable actuator and at least one movable Fabry-Perot filter cavity mirror coupled to the bi-stable actuator. The bi-stable actuator may be associated with a first latched position and a second latched position and may comprise, for example, a thermal device, an electrostatic device (e.g., a parallel plate or comb drive), or a magnetic device. According to some embodiments, a relationship between a voltage applied to an actuator of a Fabry-Perot filter and an amount of displacement associated with a movable mirror is substantially linear.
1. A micro-electrical mechanical system apparatus associated with a wafer having two, substantially parallel, planar surfaces, comprising:
a bi-stable micro-electrical mechanical system actuator structured to: (i) rest in a first latched position and (ii) rest in a second latched position; and
at least one movable Fabry-Perot filter cavity mirror coupled to the bi-stable actuator, wherein a reflective surface of the at least one movable Fabry-Perot filter cavity mirror is positioned between, and substantially perpendicular to, the two planar surfaces of the wafer, the bi-stable actuator being oriented substantially within a plane defined by one of the planar surfaces of the wafer.
2. The apparatus of claim 1 , wherein the bi-stable actuator is structured such that the actuator does not rest in positions other than the first and second latched positions.
3. The apparatus of claim 2 , wherein the bi-stable actuator comprises at least one of: (i) a thermal device, (ii) an electrostatic device, or (iii) a magnetic device.
4. The apparatus of claim 1 , further comprising:
a fixed mirror having a reflective surface positioned substantially parallel to the reflective surface of the movable mirror.
5. The apparatus of claim 4 , wherein the at least one movable Fabry-Perot filter cavity mirror comprises a spectrometer cavity mirror.
6. The apparatus of claim 5 , further comprising:
a light source.
7. The apparatus of claim 6 , wherein the light source is broadband light scattered from an analyte sample.
8. The apparatus of claim 7 , further comprising:
a sensor to sense photons exiting the at least one movable Fabry-Perot filter cavity mirror over time as the at least one movable Fabry-Perot filter cavity mirror is moved by the bi-stable actuator.
9. The apparatus of claim 4 , wherein at least one of the movable or fixed mirrors comprises a crystallographic plane of silicon.
10. The apparatus of claim 1 , wherein the at least one movable Fabry-Perot filter cavity mirror comprises at least one of: (i) a telecommunication device cavity mirror, (ii) a meteorology device cavity mirror, or (iii) a pressure sensor cavity mirror.
11. A method, comprising:
routing light from a sample of molecules into a tunable Fabry-Perot cavity associated with a wafer having two, substantially parallel, planar surfaces;
moving a Fabry-Perot filter cavity mirror, using a bi-stable micro-electrical mechanical system actuator structured to: (i) rest in a first latched position and (ii) rest in a second latched position, wherein the mirror is moved between the first latched position and the second latched position and the distances between the first and second latched positions are associated with a spectral range of light wavelengths; and
detecting interference patterns across the spectral range, wherein a reflective surface of the Fabry-Perot filter cavity mirror is positioned between, and substantially perpendicular to, the two planar surfaces of the wafer, the bi-stable actuator being oriented such that the first and second latched positions are both substantially within a plane defined by one of the planar surfaces of the wafer.
12. The method of claim 11 , further comprising:
comparing the detected interference pattern with a signature pattern associated with a particular molecule.
13. The method of claim 11 , further comprising:
providing an indication based on said comparing.
14. A spectrometer, comprising:
a laser source;
an analyte sample to reflect light from the laser source;
a Fabry-Perot filter cavity portion to receive the reflected light, including:
a bi-stable micro-electrical mechanical system actuator oriented within a plane defined by a top surface of a silicon wafer and structured to: (i) rest in a first latched position and (ii) rest in a second latched position, wherein the bi-stable actuator is further structured so as to not rest in positions other than the first and second latched positions,
a movable Fabry-Perot filter cavity mirror coupled to the bi-stable actuator, the movable mirror being formed of a crystallographic plane of silicon having a reflective surface positioned vertically within the silicon wafer and substantially perpendicular to the top surface of the silicon wafer, and
a fixed Fabry-Perot filter cavity mirror having a reflective surface positioned vertically within the silicon wafer, substantially perpendicular to the top surface of the silicon wafer, and substantially parallel to the movable mirror;
a detector to detect photons exiting the Fabry-Perot filter cavity over time as the movable mirror is moved by the actuator; and
a decision unit to determine if the analyte sample is associated with at least one type of molecule based on the sensed photons.
15. The spectrometer of claim 14 , wherein the spectrometer comprises at least one of (i) a Raman device, (ii) an infra-red absorption device, or (iii) or a fluorescence spectroscopy device.
16. The spectrometer of claim 14 , wherein the bi-stable actuator comprises at least one of: (i) a thermal device, (ii) an electrostatic device, or (iii) a magnetic device.