Optical reflection element
An optical reflecting element includes a mirror, and a pair of high-frequency vibrators and a pair of low-frequency vibrators for vibrating the mirror. The high-frequency vibrators include a substrate, a bottom electrode layer formed on the substrate, a piezoelectric layer, and a drive electrode and a first monitor electrode as the top electrode layer. One end of the low-frequency vibrator has the substrate shared with the high-frequency vibrator, a bottom electrode layer, a piezoelectric layer, a drive electrode, and a second monitor electrode as the top electrode layer. The other end of the low-frequency vibrator has the substrate shared with the high-frequency vibrator, a bottom electrode layer, a piezoelectric layer, a drive electrode, a first monitor electrode, and an insulator layer as a dead zone for preventing a piezoelectric effect due to the piezoelectric layer from reaching the first monitor electrode. The first monitor electrode provided on the low-frequency vibrator is connected from the top of the vibrator to an extraction electrode.
1. An optical reflecting element comprising:
a frame-shaped support body;
a first low-frequency vibrator whose first end is connected to an inside of the support body;
a second low-frequency vibrator whose first end is connected to an inside of the support body;
a frame of which outside is connected to second ends of the first and second low-frequency vibrators, the frame disposed between the first and second low-frequency vibrators;
a first high-frequency vibrator whose first end is connected to an inside of the frame;
a second high-frequency vibrator whose first end is connected to an inside of the frame; and
a mirror connected to second ends of the first and second high-frequency vibrators, the mirror disposed between the first and second high-frequency vibrators,
wherein each of the first and second high-frequency vibrators includes:
a first drive unit for rotating the mirror around a first central axis of the first and second high-frequency vibrators; and
a first monitor element for measuring a rotation amount of the mirror,
wherein the first drive unit includes:
a substrate;
a bottom electrode layer provided on the substrate;
a piezoelectric layer provided on the bottom electrode layer; and
a drive electrode provided on the piezoelectric layer,
wherein the first monitor element includes:
the substrate shared with the first drive unit;
the bottom electrode layer shared with the first drive unit;
the piezoelectric layer shared with the first drive unit; and
a first monitor electrode provided on the piezoelectric layer,
wherein each of the first and second low-frequency vibrators includes a second drive unit for rotating the frame and the mirror around a second central axis perpendicular to the first central axis,
wherein the second drive unit includes:
the substrate shared with the first drive unit;
the bottom electrode layer shared with the first drive unit;
the piezoelectric layer shared with the first drive unit; and
the drive electrode shared with the first drive unit,
wherein the first low-frequency vibrator further includes:
the first monitor electrode shared with the first and second high-frequency vibrators; and
an insulator layer provided between the first monitor electrode and the piezoelectric layer, the insulator layer being a dead zone for preventing a piezoelectric effect due to the piezoelectric layer from reaching the first monitor electrode,
wherein the second low-frequency vibrator further includes a second monitor element for measuring a rotation amount of the frame and the mirror, and
wherein the first monitor electrode provided on the first low-frequency vibrator extends from a top of the first low-frequency vibrator to the support body and is connected to an extraction electrode provided on the support body.
2. The optical reflecting element of claim 1 ,
wherein the insulator layer of the first low-frequency vibrator is provided on the piezoelectric layer provided above the substrate, and
wherein the first monitor electrode of the first low-frequency vibrator is provided on the insulator layer.
3. The optical reflecting element of claim 1 ,
wherein the insulator layer of the first low-frequency vibrator is provided on the substrate, and
wherein the first monitor electrode of the first low-frequency vibrator is provided on the insulator layer.
4. The optical reflecting element of claim 1 ,
wherein a dividing groove is provided between each of: the drive electrode and the first monitor electrode of the first low-frequency vibrator; the drive electrode and the second monitor electrode of the second low-frequency vibrator; and the drive electrode of the first and second high-frequency vibrators and the first monitor electrode of the first and second high-frequency vibrators, and wherein each of the dividing grooves is deep enough to divide at least the bottom electrode layer.
5. The optical reflecting element of claim 1 , wherein the first and second low-frequency vibrators and the first and second high-frequency vibrators have a frequency ratio ranging from approximately 10 times to 200 times.
6. The optical reflecting element of claim 1 , wherein each of the first and second high-frequency vibrators and each of the first and second low-frequency vibrators are disposed such the first central axis and second central axis intersect at right angles at a barycenter of the mirror.
7. The optical reflecting element of claim 4 , wherein a bottom surface of the dividing groove is flat.
8. The optical reflecting element of claim 4 , wherein a cross-sectional bottom surface of the dividing groove is gradually deeper moving from an outer circumference towards a center thereof.
9. The optical reflecting element of claim 5 , wherein the first and second low-frequency vibrators and the first and second high-frequency vibrators have a frequency ratio of approximately 50 times.
10. The optical reflecting element of claim 1 , wherein the first and second high-frequency vibrators have a bend connecting adjacent diaphragms, the bend connecting the adjacent diaphragms being parallel with the first central axis.