Movable reflective element and two-dimensional scanning device

Patent metadata

Field	Value
Publication number	US-10481391-B2
Application number	US-201615579547-A
Country	US
Kind code	B2
Filing date	Jun 6, 2016
Priority date	Jun 9, 2015
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

Actuators (140), which are a pair of members, are disposed one on either side of a movable frame (120) in the X-axis direction, and oscillate the movable frame (120) about the X axis in relation to a fixed frame (110) by deformation caused by stretching and contracting of piezoelectric elements. Actuators (150), which are a pair of members, are disposed one on either side of a mirror (130) in the Y-axis direction, and oscillate the mirror (130) about the Y axis in relation to the movable frame (120) by deformation caused by stretching and contracting of the piezoelectric elements. The length of each actuator (140) extending in the Y-axis direction is longer than a distance between an inner side of the fixed frame (110) to which the actuator (140) is connected and the middle point of an outer side of the movable frame (120) in the Y-axis direction.

First claim

The invention claimed is:

1. A movable reflective element, comprising:
a plate-like fixed frame;
a plate-like movable frame disposed within the fixed frame to define a gap between the movable frame and the fixed frame;
a plate-like mirror including a reflective surface and disposed within the movable frame to define a gap between the mirror and the movable frame;
first actuators that are a pair of linear flexible members, each first actuator connecting the fixed frame to the movable frame and including piezoelectric elements formed in an extension extending in a first direction from an inner side of the fixed frame, the piezoelectric elements stretching and contracting in the first direction, the first actuators being disposed one on either side of the movable frame in a second direction that intersects the first direction, wherein deformation of the first actuators caused by stretching and contracting of the piezoelectric elements oscillates the movable frame about a first rotation axis in relation to the fixed frame; and
second actuators that are a pair of linear flexible members, each second actuator connecting the movable frame to the mirror and including piezoelectric elements formed in an extension extending in the second direction from an inner side of the movable frame, the piezoelectric elements stretching and contracting in the second direction, the second actuators are disposed one on either side of the mirror in the first direction, wherein deformation of the second actuators caused by stretching and contracting of the piezoelectric elements oscillates the mirror about a second rotation axis in relation to the movable frame, the second rotation axis intersecting the first rotation axis,
wherein the extension of each first actuator in the first direction has a length that is longer than a distance between the inner side of the fixed frame to which the first actuator is connected and a middle point of an outer side of the movable frame in the first direction.

2. The movable reflective element according to claim 1 , wherein each first actuator comprises:
a first arm including the piezoelectric elements and having one end connected to the inner side of the fixed frame, the first arm linearly extending in the first direction in the gap between the fixed frame and the movable frame from the one end beyond the middle point of the outer side of the movable frame;
a second arm having one end connected to another end of the first arm, the second arm extending in the second direction; and
a third arm having one end connected to another end of the second arm and another end connected to the middle point of the outer side of the movable frame, the third arm extending along the first arm from the other end of the second arm in a direction opposite to a direction extending from the one end to the other end of the first arm.

3. The movable reflective element according to claim 2 , wherein each second actuator comprises:
a fourth arm including the piezoelectric elements and having one end connected to the inner side of the movable frame, the fourth arm linearly extending in the second direction in the gap between the movable frame and the mirror from the one end beyond a middle point of an outer side of the mirror;
a fifth arm having one end connected to another end of the fourth arm, the fifth arm extending in the first direction; and
a sixth arm having one end connected to another end of the fifth arm and another end connected to the middle point of the outer side of the mirror in the second direction, the sixth arm extending along the fourth arm from the other end of the fifth arm in a direction opposite to a direction extending from the one end to the other end of the fourth arm.

4. The movable reflective element according to claim 3 , wherein
the first actuators that are the pair of members are disposed with two-fold rotational symmetry around the mirror,
the second actuators that are the pair of members are disposed with two-fold rotational symmetry around the mirror, and
an orientation of the first arm from the one end to the other end and an orientation of the fourth arm from the one end to the other end are the same with respect to a rotational direction about the mirror.

5. The movable reflective element according to claim 3 , wherein
the first actuators that are the pair of members are disposed with two-fold rotational symmetry around the mirror,
the second actuators that are the pair of members are disposed with two-fold rotational symmetry around the mirror, and
an orientation of the first arm from the one end to the other end and an orientation of the fourth arm from the one end to the other end are opposite with respect to a rotational direction about the mirror.

6. The movable reflective element according to claim 2 , wherein each second actuator comprises a seventh arm including the piezoelectric elements and having one end connected to the inner side of the movable frame and another end connected to a corner portion of the mirror, the seventh arm extending linearly in the second direction in the gap between the movable frame and the mirror from the one end beyond a middle point of an outer side of the mirror.

7. The movable reflective element according to claim 1 , wherein
each first actuator comprises an eighth arm including the piezoelectric elements and having one end connected to the inner side of the fixed frame and extending linearly in the first direction in the gap between the fixed frame and the movable frame from the one end beyond the middle point of the outer side of the movable frame, and
each first actuator is connected to the movable frame at a portion other than the middle point of the outer side of the movable frame without turning back at another end of the eighth arm.

8. The movable reflective element according to claim 7 , wherein each first actuator comprises a ninth arm extending in the second direction in the gap between the fixed frame and the movable frame from the other end of the eighth arm beyond the middle point of the outer side of the movable frame in the second direction and connected to a corner portion of the movable frame.

9. The movable reflective element according to claim 7 , wherein
each second actuator comprises a tenth arm including the piezoelectric elements and having one end connected to the inner side of the movable frame and extending linearly in the second direction in the gap between the movable frame and the mirror from the one end beyond the middle point of the outer side of the mirror, and
each second actuator is connected to the mirror at a portion other than the middle point of the outer side of the mirror along the second direction without turning back at another end of the tenth arm.

10. The movable reflective element according to claim 9 , wherein each second actuator comprises an eleventh arm extending in the first direction from the other end of the tenth arm beyond a middle point of the outer side of the mirror in the first direction and connected to a corner portion of the mirror.

11. The movable reflective element according to claim 1 , wherein
the movable frame includes recessed portions provided on two outer sides in the second direction, and
each first actuator comprises:
a twelfth arm including the piezoelectric elements and having one end connected to the inner side of the fixed frame, the twelfth arm extending linearly in the first direction in the gap between the fixed frame and the movable frame from the one end beyond the middle point of the outer side of the movable frame;
a thirteenth arm extending in the second direction from another end of the twelfth arm to a middle point of the outer s

Assignees

• Dai Ichi Seiko Co Ltd

Inventors

• Ogata Kenji
• Sakamoto Shinya
• Ikeda Yoshifumi
• KUROGI Shogo
• Okada Kazuhiro
• Era Satoshi

Classifications

• B81B2203/0181

  See-saws · CPC title

• B81B2203/0172

  Flexible holders not provided for in B81B2203/0154 - B81B2203/0163 · CPC title

• B81B3/0045

  Improve properties related to angular swinging, e.g. control resonance frequency · CPC title

• B81B2201/042

  Micromirrors, not used as optical switches · CPC title

• B81B2203/058

  Rotation out of a plane parallel to the substrate · CPC title