Piezoelectrically-activated cantilevered spatial light modulator
View Patent ↗A piezoelectric spatial light modulator including a substrate having an array of cavities and piezoelectric cantilevers is arranged on the substrate. Each of the piezoelectric cantilevers includes a base portion on the substrate and a beam portion extending over a respective one of the cavities. Each of the piezoelectric cantilevers further includes a first electrode, a second electrode and a piezoelectric element between the electrodes. A flexible layer covers the cavities and the piezoelectric cantilevers and reflective elements are each located on the flexible layer over a respective one of the beam portions.
1. A piezoelectric spatial light modulator, comprising:
a substrate having an array of cavities; and
piezoelectric cantilevers arranged on the substrate, each of the piezoelectric cantilevers comprising a base portion on the substrate and a beam portion extending over a respective one of the cavities, each of the piezoelectric cantilevers further comprising a first electrode, a second electrode and a piezoelectric element between the electrodes;
a flexible layer covering the cavities and the piezoelectric cantilevers; and
reflective elements, each located on the flexible layer over a respective one of the beam portions.
2. The piezoelectric spatial light modulator of claim 1 , additionally comprising a transistor electrically connected to one of the electrodes of each one of the piezoelectric cantilevers.
3. The piezoelectric spatial light modulator of claim 1 , in which:
the piezoelectric element is a first piezoelectric element; and
each of the piezoelectric cantilevers additionally comprises a third electrode and a second piezoelectric element between the second electrode and the third electrode.
4. The piezoelectric spatial light modulator of claim 3 , additionally comprising a transistor electrically connected to one of the electrodes of each one of the piezoelectric cantilevers.
5. The piezoelectric spatial light modulator of claim 4 , in which the transistor is one of a PMOS and an NMOS metal-oxide-semiconductor transistor and each comprises a source contact, a gate contact and a drain contact, the source contact connected to receive a reference voltage, the gate contact connected to receive an activation signal, and the drain contact connected to the second electrode.
6. The piezoelectric spatial light modulator of claim 3 , additionally comprising a first transistor electrically connected to one of the electrodes of the first piezoelectric element in each of the piezoelectric cantilevers and a second transistor electrically connected to one of the electrodes of the second piezoelectric element in each of the piezoelectric cantilevers.
7. The piezoelectric spatial light modulator of claim 6 , in which the first transistor and the second transistor are each one of a PMOS and an NMOS metal-oxide-semiconductor transistor and each comprises a source contact, a gate contact and a drain contact, the source contacts connected to receive a common reference voltage, the gate contacts connected to receive an activation signal, the drain contact of the first transistor connected to the first electrode, and the drain contact of the second transistor connected to the third electrode.
8. The piezoelectric spatial light modulator of claim 3 , in which the first electrode, the second electrode and the third electrode comprise one of gold, silver, platinum, palladium, copper, aluminum, and alloys thereof.
9. The piezoelectric spatial light modulator of claim 1 , in which the piezoelectric cantilever additionally comprises a support layer between the second electrode and the substrate.
10. The piezoelectric spatial light modulator of claim 9 , in which the support layer comprises one of silicon nitride and silicon oxide.
11. The piezoelectric spatial light modulator of claim 1 , in which the substrate comprises glass.
12. The piezoelectric spatial light modulator of claim 1 , in which the piezoelectric element comprises one of lead zirconate titanate, lead lanthanum zirconate titanate, lead magnesium niobate-lead zirconate titanate, lead zirconate niobate-lead zirconate titanate, aluminum nitride, and zinc oxide.
13. The piezoelectric spatial light modulator of claim 1 , in which the piezoelectric element comprises lead zirconate titanate with a zirconate to titanate molar ratio of about 0.4 to about 0.6.
14. The piezoelectric spatial light modulator of claim 1 , in which the first electrode and the second electrode each comprise a layer of platinum and a layer of one of titanium and titanium oxide.
15. The piezoelectric spatial light modulator of claim 1 , in which the flexible layer comprises polyimide.
16. The piezoelectric spatial light modulator of claim 1 , in which the array of cavities is periodic.
17. The piezoelectric spatial light modulator of claim 1 , in which the substrate has a first surface and a second surface opposite thereto, and the cavities extend through the substrate between the first surface and the second surface.
18. The piezoelectric spatial light modulator of claim 1 , in which the substrate has a first surface and the cavities extend into the substrate from the first surface.
19. The piezoelectric spatial light modulator of claim 1 , in which shape of the reflective elements is one of planar and concave.
20. A piezoelectric spatial light modulator, comprising:
a substrate having an array of cavities; and
piezoelectric cantilevers arranged on the substrate, each of the piezoelectric cantilevers comprising a base portion on the substrate and a beam portion extending over a respective one of the cavities, each of the piezoelectric cantilevers further comprising a first electrode, a second electrode and a piezoelectric element between the electrodes;
a first transistor electrically connected to one of the electrodes of each of the piezoelectric cantilevers; and
reflective elements, each located over a respective one of the beam portions.
21. The piezoelectric spatial light modulator of claim 20 , in which:
the piezoelectric element is a first piezoelectric element; and
each of the piezoelectric cantilevers additionally comprises a third electrode and a second piezoelectric element between the second electrode and the third electrode; and
additionally comprising a second transistor electrically connected to another of the electrodes of each of the piezoelectric cantilevers, wherein the first transistor is electrically connected to one of the electrodes of the first piezoelectric element in each of the piezoelectric cantilevers and the second transistor is electrically connected to another of the electrodes of the second piezoelectric element in each of the piezoelectric cantilevers.