Direct drive MEMS scanning micromirror
A direct drive scanning micromirror includes a mirror body defining a mirror surface, and a plurality of curved cantilevers that each extend directly from the mirror body. The shape of the cantilevers and the geometry of the interface between the cantilevers and the mirror body are configured to decrease peak stresses within the micromirror during operation, which may beneficially impact performance and lifetime.
1 . An artificial reality optical display comprising:
a direct drive scanning micromirror comprising:
a mirror body defining a mirror surface; and
at least three curved cantilevers extending directly from the mirror body, wherein a width of each of the at least three curved cantilevers increases with decreasing distance from the mirror body.
2 . The artificial reality optical display of claim 1 , wherein the mirror body comprises a circular shape.
3 . The artificial reality optical display of claim 1 , wherein the mirror body comprises an elliptical shape.
4 . The artificial reality optical display of claim 1 , wherein the mirror body comprises a non-uniform thickness.
5 . The artificial reality optical display of claim 1 , wherein the mirror body comprises a plurality of raised ribs or pillars on a surface of the mirror body opposite to the mirror surface.
6 . The artificial reality optical display of claim 1 , further comprising an aperture extending entirely through the mirror body.
7 . The artificial reality optical display of claim 1 , wherein a radius of curvature of each of the at least three curved cantilevers is less than a radius of curvature of the mirror body.
8 . The artificial reality optical display of claim 1 , wherein a radius of curvature of each of the at least three curved cantilevers varies as a function of position.
9 . The artificial reality optical display of claim 1 , wherein a shape of the micromirror is rotationally asymmetric.
10 . The artificial reality optical display of claim 1 , wherein the at least three curved cantilevers each comprise:
a primary electrode;
a secondary electrode overlapping at least a portion of the primary electrode; and
a layer of piezoelectric material disposed between the primary electrode and the secondary electrode.
11 . The artificial reality optical display of claim 10 , wherein an area of the secondary electrode is less than an area of the primary electrode.
12 . The artificial reality optical display of claim 10 , wherein the layer of piezoelectric material comprises a compound selected from the group consisting of AlScN, PZT, AlN, and PMN-PT.
13 . The artificial reality optical display of claim 10 , further comprising a tertiary electrode overlapping at least a portion of the primary electrode, wherein the tertiary electrode is electrically isolated from the secondary electrode.
14 . The artificial reality optical display of claim 1 , wherein the mirror body is configured to oscillate in orthogonal tip and tilt resonance modes with an inter-mode frequency ratio of approximately 1:1.
15 . Augmented reality glasses comprising the artificial reality optical display of claim 1 .
16 . An artificial reality optical display comprising:
a direct drive MEMS scanning micromirror comprising:
a mirror body defining a mirror surface; and
a plurality of curved cantilevers extending from the mirror body, wherein a width of a portion of each of the plurality of curved cantilevers decreases with increasing distance from the mirror body.
17 . The artificial reality optical display of claim 16 , wherein a shape of the micromirror viewed along a direction substantially orthogonal to the mirror surface is rotationally asymmetric.
18 . The artificial reality optical display of claim 16 , comprising a first pair of opposing curved cantilevers having a first shape and a second pair of opposing curved cantilevers having a second shape different from the first shape.