Optical scanning apparatus having pivoting reflector and piezoelectric element

Patent metadata

Field	Value
Publication number	US-10459217-B2
Application number	US-201615547218-A
Country	US
Kind code	B2
Filing date	Mar 25, 2016
Priority date	Apr 15, 2015
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

A reflector has a reflective surface on first and second directions. Each of torsion beams extends to each opposite side of the reflective surface in the first direction. Each of coupling portions is to each opposite side of the reflector in the first direction and includes a central portion with U-shape having two projection portions and a bottom portion joined to the torsion beam. The projection portions include first concave portions opposing across the torsion beam by being penetrated in thickness direction. Each first concave portion extends in the second direction from an opening to a side surface facing the torsion beam towards an opposite side surface up to a bottom. A distance between the bottoms of the first concave portions across the torsion beam is greater than a distance between the side surfaces each facing the torsion beam of the projection portions.

First claim

The invention claimed is:

1. An optical scanning apparatus comprising:
a reflector that includes a reflective surface reflecting a light beam, the reflective surface perpendicular to a thickness direction, the reflective surface having a first direction and a second direction perpendicular to the first direction;
torsion beams between which the reflector is centered, the torsion beams extending from the reflector to opposite sides of the reflector in the first direction, respectively, the torsion beams enabling the reflector to pivot about an axis parallel to the first direction;
coupling portions disposed at opposite sides in the first direction, the coupling portions opposing each other across the reflector,
each of the coupling portions including
(i) a central portion having a U-shape including a bottom portion and two projection portions, the central portion opening toward the reflector when viewing the reflective surface from above in the thickness direction,
the bottom portion of the U-shape being joined to an end of the torsion beam, the end of the torsion beam being opposite to an end of the torsion beam joined to the reflector,
the two projection portions of the U-shape opposing each other to sandwich the torsion beam, and

(ii) opposite end portions that respectively extend in the second direction outwardly from opposite ends of the central portion in the second direction; and

supporting portions disposed at opposite sides in the second direction, the supporting portions opposing each other across the reflector,
each of the supporting portions extending between opposite ends in the first direction,
each of the supporting portions being joined to each of opposite ends of the coupling portion in the second direction,

wherein:
the central portion of the coupling portion is provided with first concave portions opposing each other in the projection portions of the U-shape, each projection portion having (i) a side surface facing the torsion beam and (ii) an opposite side surface opposite to the side surface facing the torsion beam in the second direction,
each first concave portion having a concaved shape being concaved by penetrating the coupling portion in the thickness direction perpendicular to the reflective surface,
each first concave portion having an opening to the side surface facing the torsion beam and extending from the opening towards the opposite side surface in the second direction up to a bottom, when viewing the reflective surface from above in the thickness direction;

a distance in the second direction between, of the concaved shapes of the first concave portions in the coupling portion, the bottoms opposing each other across the torsion beam is set greater than a distance in the second direction between, of the two projection portions of the U-shape, the side surfaces facing the torsion beam opposing each other across the torsion beam;
the central portion of the coupling portion is provided with a second concave portion in a portion closer to the reflector than the first concave portion in the first direction,
the second concave portion having a concaved shape being concaved by penetrating the coupling portion in the thickness direction perpendicular to the reflective surface,
the second concave portion
opening to the opposite side surface of each projection portion of the central portion and
extending towards the side surface facing the torsion beam;

a piezoelectric element configured by laminating a lower electrode, a piezoelectric film, and an upper electrode is formed to a surface of a portion ranging from each of the opposite end portions to the central portion, the portion being closer to the reflector than the second concave portion in the first direction; and
the piezoelectric element is formed up to a tip end of the central portion, the tip end adjacent to the torsion beam.

2. The optical scanning apparatus according to claim 1 , wherein
the central portion is formed to be folded in an arc shape around the bottom of the concaved shape of the first concave portion.

3. The optical scanning apparatus according to claim 1 , wherein:
a third concave portion having a concaved shape being concaved is provided by penetrating the coupling portion and the torsion beam in the thickness direction,
the third concave portion opening to a side surface of the central portion, the side surface being formed in the thickness direction and oppositely to the reflector in the first direction,
the third concave portion extending from the side surface of the central portion toward the reflector in the first direction; and

the torsion beam is provided as two torsion beam units due to the third concave portion, the two torsion beam units being parallel to the first direction by opposing each other at opposite sides in the second direction and extending in the first direction.

4. The optical scanning apparatus according to claim 1 , wherein
the first concave portion is formed as opening to a portion farthest from the reflector in the first direction in the side surface facing the torsion beam of the central portion.

Assignees

• Denso Corp

Inventors

• Oyama Koichi
• Nishikawa Hideaki
• Kawai Yusuke
• Sakai Kenichi

Classifications

• B81B2203/0154

  Torsion bars · CPC title

• H02N2/10

  producing rotary motion, e.g. rotary motors · CPC title

• B81B2201/042

  Micromirrors, not used as optical switches · CPC title

• B81B2203/019

  characterized by their profile · CPC title

• G02B26/105

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