Micromechanical device and method for the two-dimensional deflection of light

Patent metadata

Field	Value
Publication number	US-10241323-B2
Application number	US-201715688038-A
Country	US
Kind code	B2
Filing date	Aug 28, 2017
Priority date	Sep 7, 2016
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

A micromechanical device and a method for the two-dimensional deflection of light. The device includes a mirror unit having a mirror surface for deflecting light striking the mirror surface; the mirror unit being rotatably situated about a first axis within a first frame unit and being fastened to the first frame unit; the first frame unit being rotatably situated about a second axis within an actuator structure and being fastened to the actuator structure; the actuator structure including at least four piezoelectric actuator units; and the positions of the at least four piezoelectric actuator units being situated symmetrically with respect to the first axis and also with respect to the second axis.

First claim

What is claimed is:

1. A micromechanical device for the two-dimensional deflection of light, comprising:
a first frame unit;
an actuator structure that includes at least four piezoelectric actuator units; and
a mirror unit that:
has a mirror surface for deflecting light striking the mirror surface; and
is rotatably situated about a first axis of rotation within, and fastened to, the first frame unit;

wherein:
the first frame unit is rotatably situated about a second axis of rotation within, and fastened to, the actuator structure;
the at least four piezoelectric actuator units are positioned symmetrically both with respect to the first axis and with respect to the second axis; and
any one or more of the following four features (a)-(d):
(a) a direction in which one of the first and second axes extends is parallel to respective directions in which respective central longitudinal axes of the at least four piezoelectric actuator units extend;
(b) different ones of the at least four piezoelectric actuator units are simultaneously movable so that their respective central longitudinal axes, which, when the micromechanical device is at rest, all extend along and within a same plane, instead simultaneously extend along and within respective planes, of which at least two are different than each other;
(c) for each of the at least four piezoelectric actuator units, the respective piezoelectric actuator unit is actuatable by application of voltage between a respective pair of electrodes between which piezoelectric material of the respective piezoelectric actuator unit is arranged; and
(d) the at least four piezoelectric actuator units include first, second, third, and fourth piezoelectric actuator units arranged to:
respond to application of a first set of voltages by (1) the first and second piezoelectric actuator units shifting in a first direction that is perpendicular to the first and second axes and (2) the third and fourth piezoelectric actuator units shifting in an opposite second direction that is perpendicular to the first and second axes; and
respond to application of a second set of voltages by (1) the second and fourth piezoelectric actuator units shifting in the first direction and (2) the first and third piezoelectric actuator units shifting in the second direction.

2. The device as recited in claim 1 , wherein the dimensions of the at least four piezoelectric actuator units are identical in a first direction in parallel to the first axis, and the dimensions of the at least four piezoelectric actuator units are identical in a second direction in parallel to the second axis.

3. The device as recited in claim 1 , wherein each of the piezoelectric actuator units is connected via one bending beam each to the rest of the device.

4. The device as recited in claim 3 , wherein the first frame unit is connected to the actuator structure via two torsion beams, and wherein each of the torsion beams engages in a respective area of the actuator structure, in which two bending beams each meet.

5. The device as recited in claim 3 , wherein the piezoelectric actuator units have a rectangular shape with two shorter sides and two longer sides, and each of the bending beams engage the respective actuator unit on a respective end of one of the longer sides.

6. The device as recited in claim 1 , wherein the piezoelectric actuator units are electrically contacted with the aid of electrical lines in such a way that a respective voltage is applicable to each of the actuator units via the electrical lines in a direction that is oriented perpendicular to a plane spanned by the first axis and the second axis.

7. The device as recited in claim 1 , wherein the piezoelectric actuator units are electrically contacted with the aid of electrical lines in such a way that a periodic electrical signal having the same amplitude and having an adjustable, relative phase shift of 0° or 180°, respectively, is applicable to each of the actuator units.

8. The device as recited in claim 1 , wherein the direction in which the one of the first and second axes extends is parallel to the respective directions in which the respective central longitudinal axes of the at least four piezoelectric actuator units extend.

9. The device as recited in claim 8 , wherein the one of the first and second axes is the second axis.

10. The device as recited in claim 1 , wherein each of the longitudinal axes of the at least four piezoelectric actuator units is either parallel to or the same as all others of the longitudinal axes of the at least four piezoelectric actuator units.

11. The device as recited in claim 1 , wherein a longitudinal axis of at least one of the at least four piezoelectric actuator units is the same as that of at least one other of the at least four piezoelectric actuator units.

12. The device as recited in claim 1 , wherein the different ones of the at least four piezoelectric actuator units are simultaneously movable so that their respective central longitudinal axes extend along and within the different respective planes that include the planes that are non-parallel to each other.

13. The device as recited in claim 1 , wherein for each of the at least four piezoelectric actuator units, the respective piezoelectric actuator unit is actuatable by the application of voltage between the respective pair of electrodes between which the piezoelectric material of the respective piezoelectric actuator unit is arranged.

14. The device as recited in claim 13 , wherein for each of the piezoelectric actuator units, the respective applied voltage is applied between the respective pair of electrodes through the piezoelectric material in a direction that is perpendicular to each of the first and second axes.

15. The device as recited in claim 1 , wherein the at least four piezoelectric actuator units include the first, second, third, and fourth piezoelectric actuator units arranged to:
respond to the application of the first set of voltages by (a) the first and second piezoelectric actuator units shifting in the first direction and (b) the third and fourth piezoelectric actuator units shifting in the opposite second direction; and
respond to application of a second set of voltages by (a) the second and fourth piezoelectric actuator units shifting in the first direction and (b) the first and third piezoelectric actuator units shifting in the second direction.

16. A method for the two-dimensional deflection of light using a micromechanical device, the micromechanical device including (a) a first frame unit, (b) an actuator structure that includes at least four piezoelectric actuator units, and (c) a mirror unit that (1) has a mirror surface for deflecting light striking the mirror surface, and (2) is rotatably situated about a first axis within, and fastened to, the first frame unit, the first frame unit being rotatably situated about a second axis within, and fastened to, the actuator structure, wherein the at least four piezoelectric actuator units are positioned symmetrically both with respect to the first axis and with respect to the second axis, the method comprising:
applying a first periodic voltage signal to a first piezoelectric actuator unit of the at least four piezoelectric actuator units; and
applying a second periodic voltage signal to a second piezoelectric actuator unit of the at least four piezoelectric actuator units;
wherein:
the first and second voltage signals are applied in such a way that an instantaneous amplitude of the second voltage signal is either equal to an instantaneous amplitude of the first voltage sign

Assignees

• Bosch Gmbh Robert

Inventors

• Hattass Mirko
• Maul Robert

Classifications

• G02B26/101

  with both horizontal and vertical deflecting means, e.g. raster or XY scanners (colour television using laser beams scanning a display screen H04N9/3129) · CPC title

• G02B7/182

  for mirrors · CPC title

• G02B26/0858 Primary

  the reflecting means being moved or deformed by piezoelectric means · CPC title

• G02B26/105 Primary

  with one or more pivoting mirrors or galvano-mirrors (G02B26/101 takes precedence) · CPC title