WO2019167616A1

WO2019167616A1 - Optical deflector

Info

Publication number: WO2019167616A1
Application number: PCT/JP2019/004982
Authority: WO
Inventors: 友崇矢部; 研至河合; 大島　清朗
Original assignee: パイオニア株式会社
Priority date: 2018-02-27
Filing date: 2019-02-13
Publication date: 2019-09-06

Abstract

Provided is an optical deflector capable of increasing the oscillation angle of a reflective plate. Inhibitive deformation (e.g., deformation whereby a base section main body (41) deflects in the X direction) that inhibits normal deformation of a base section (4) (e.g., deformation whereby the base section main body (41) deflects in the Y direction) is suppressed by the base section (4) having a deformation suppressing section (43). As a result, a drive element (5) can easily cause normal deflection of the base section (4) and the oscillation angle of the reflective plate (2) can be increased.

Description

Optical deflector

The present invention relates to an optical deflector.

Conventionally, an optical deflector for scanning light has been proposed in which a mirror portion (reflecting plate) is swung by a piezoelectric actuator (driving element) (see, for example, Patent Document 1). In the optical deflector described in Patent Document 1, the mirror portion is swung (rotated) by supplying an AC drive signal having a resonance frequency to the piezoelectric actuator.

JP 2016-085299 A

In the configuration in which the reflection plate is rotated using resonance as described in Patent Document 1, the base portion that supports the reflection plate is deformed via the shaft portion, and this deformation (vibration) is transmitted to the reflection plate. It is like that. However, the base portion may be deformed in a plurality of directions and may include deformation that does not contribute to the rotation of the reflecting plate. Such deformation can be a factor that inhibits deformation that contributes to the rotation of the reflector. That is, there is an inconvenience that the swing angle of the obtained reflector becomes small with respect to the driving force of the driving element.

Therefore, an object of the present invention is to provide an optical deflector that can increase the swing angle of the reflector as an example.

In order to solve the above-described problems and achieve the object, an optical deflector according to the present invention includes a reflecting plate, a pair of shaft portions that define a rotation axis of the reflecting plate, and the pair of shafts. A base part for supporting the part, and a driving element for rotating the reflecting plate by deforming the base part, wherein the base part is for deforming the base part for rotating the reflecting plate. It has the deformation | transformation suppression part which suppresses the inhibition deformation | transformation used as inhibition.

It is a top view which shows the optical deflector which concerns on the Example of this invention. It is a bottom view which shows the said optical deflector. It is sectional drawing which shows the 1st process of forming a deformation | transformation suppression part in a base part in the said optical deflector. It is sectional drawing which shows the 2nd process of forming a deformation | transformation suppression part in a base part in the said optical deflector. It is sectional drawing which shows the 3rd process of forming a deformation | transformation suppression part in a base part in the said optical deflector. It is sectional drawing which shows the 4th process of forming a deformation | transformation suppression part in a base part in the said optical deflector. It is sectional drawing which shows the 5th process of forming a deformation | transformation suppression part in a base part in the said optical deflector. It is a bottom view which shows the optical deflector which concerns on the 1st modification of this invention. It is a bottom view which shows the optical deflector which concerns on the 2nd modification of this invention. It is a top view which shows the optical deflector which concerns on the 3rd modification of this invention. It is a bottom view which shows the said optical deflector. It is a top view which shows the optical deflector which concerns on the 4th modification of this invention. It is a bottom view which shows the said optical deflector.

Hereinafter, embodiments of the present invention will be described. An optical deflector according to an embodiment of the present invention includes a reflecting plate, a pair of shaft portions that define a rotation axis of the reflecting plate, a base portion that supports the pair of shaft portions, and a reflecting plate that deforms the base portion. And a drive element for rotating. The base portion has a deformation suppressing portion that suppresses the obstructive deformation that becomes an obstruction of the deformation of the base portion for rotating the reflecting plate.

When the base portion is deformed by the driving element, a deformation for rotating the reflecting plate (positive deformation; for example, a deformation that warps with respect to the surface direction of the reflecting plate and the direction orthogonal to the rotation axis), and the reflecting plate is rotated. Deformation that inhibits deformation for movement (inhibition deformation; for example, deformation that warps with respect to the surface direction of the reflecting plate and the direction of the rotation axis) may occur. By providing the deformation suppressing portion that suppresses such obstructive deformation, the base portion can be easily positively deformed by the drive element, and the swing angle of the reflecting plate can be increased.

It is preferable that the deformation suppressing portion extends along the axial direction of the rotating shaft. Thereby, the obstructive deformation that makes the base portion convex when viewed from the direction intersecting the rotation axis can be suppressed, and the swing angle of the reflector can be increased.

The base portion is arranged in parallel with the reflecting plate at a position spaced in the crossing direction with respect to the rotation axis, and the base portion main body on which the driving element is disposed, and the base portion main body extends along the crossing direction. It is preferable that a base part has what was arrange | positioned at a base part main body as a deformation | transformation suppression part. Thereby, when vibration is transmitted from the drive element to the reflecting plate, the inhibition deformation can be suppressed on the upstream side of the transmission.

The base part may have what was arrange | positioned at the beam-like part as a deformation | transformation suppression part. Thereby, when vibration is transmitted from the drive element to the reflection plate, the inhibition deformation can be suppressed on the downstream side of the transmission.

The base portion is preferably formed in a plate shape and has a deformation suppressing portion disposed on a surface opposite to the surface on which the drive element is disposed. Thereby, when arrange | positioning a drive element in a base part, it can suppress that it interferes with a deformation | transformation suppression part.

The base portion may have a portion that is arranged at a position overlapping the drive element in the thickness direction as a deformation suppressing portion. Thereby, when vibration is transmitted from the drive element to the reflecting plate, the inhibition deformation can be suppressed on the upstream side of the transmission.

It is preferable that the base portion has a surface whose one surface is formed in a convex shape or a concave shape as a deformation suppressing portion. Thereby, a deformation | transformation suppression part can be formed by shaving one surface of the plate-shaped member which comprises a base part, for example, and a number of parts can be reduced. Moreover, the base part may have what was formed separately from the plate-shaped member which comprises this base part as a deformation | transformation suppression part. Thereby, the material of a plate-shaped member and a deformation | transformation suppression part can be selected suitably.

Hereinafter, examples of the present invention will be described in detail. As shown in FIGS. 1 and 2, the optical deflector 1 A includes a reflecting plate 2, a pair of shaft portions (torsion bars) 3 A and 3 B, a base portion 4, a drive element 5, and a frame 6. The optical deflector 1A is used for scanning with infrared rays in a detection device that is mounted on a vehicle and detects the distance from other vehicles, installation objects, and the like by transmitting and receiving light such as infrared rays. In this embodiment, the axial direction of the rotation axis O of the reflecting plate 2 is defined as the X direction, and the direction perpendicular to the X direction is defined as the Y direction in the plane of the base portion 4 formed in a plate shape as will be described later. The plate thickness direction of the portion 4 is taken as the Z direction.

The reflecting plate 2 has a reflecting surface that reflects light on one side and is formed in a disc shape. The pair of shaft portions 3 A and 3 B are formed integrally with the end portions on both sides in the X direction of the reflecting plate 2 and extend along the X direction.

The base portion 4 supports a rectangular plate-like base portion main body 41 having the X direction as the long side direction and the Y direction as the short side direction, and a pair of

shaft portions

3A and 3B protruding from the base portion main body 41. Are formed in a plate shape and disposed inside the frame 6.

The long side on one side (upper side in FIG. 1) of the base part main body 41 is formed integrally with or fixed to the frame 6, and the beam-

like parts

42A and 42B are Y from both ends in the X direction on the other long side. It extends along the direction. The beam-

like portions

42A and 42B are integrally formed with the

shaft portions

3A and 3B at the end opposite to the base portion main body 41, thereby supporting the

shaft portions

3A and 3B. Thus, the base part main body 41 is juxtaposed in the Y direction with respect to the reflecting plate 2, and the beam-

like parts

42A and 42B are arranged so as to sandwich the reflecting plate 2 from the X direction.

The drive element 5 is disposed on the entire base portion main body 41 in the base portion 4. The drive element may be arranged so as to occupy a part of the entire area of the base body. For example, the drive element 5 is formed by laminating a lower electrode, a piezoelectric body, and an upper electrode in this order. The drive element 5 is deformed so as to be warped by applying a voltage between the electrodes, and the base portion with the Z direction as a vibration direction. 4 can be vibrated.

The frequency at which the drive element 5 vibrates substantially coincides with the resonance frequency of the rotating part including the reflector 2. When the drive element 5 vibrates, the base portion main body 41 is mainly bent and deformed in the Y direction (that is, the beam-

like portions

42A and 42B of the base portion main body 41 are warped with respect to the frame 6 side). This deformation is transmitted to the beam-

like portions

42A and 42B, and further transmitted to the

shaft portions

3A and 3B and the reflection plate 2, whereby the reflection plate 2 rotates about the rotation axis O. Thereby, the angle of the reflecting surface of the reflecting plate 2 changes, and it can be used for scanning by infrared rays irradiated on the reflecting surface.

The frame 6 is formed in a rectangular frame shape, and accommodates the reflecting plate 2, the

shaft portions

3A and 3B, the base portion 4 and the driving element 5 therein. Note that the frame 6 does not need to have a rectangular frame shape, and may be any shape as long as the base portion 4 is fixed, and the shape is not limited.

The base part 4 has a deformation suppressing part 43 arranged in the base part main body 41 as shown in FIG. The deformation suppression unit 43 is disposed on the surface (back surface) opposite to the surface (front surface; the surface on the reflection surface side of the reflection plate 2) on which the driving element 5 is disposed in the base body 41. Moreover, the deformation | transformation suppression part 43 is extended along the X direction so that the both ends of the X direction of the base part main body 43 may be covered. Further, the deformation suppressing unit 43 is disposed at a position overlapping the drive element 5 in the Z direction.

Further, the deformation suppressing portion 43 is a beam in which the back surface of the plate member constituting the base portion main body 41 is formed in a convex shape. Here, an example of a method for forming such a deformation suppressing portion 43 in the base portion main body 41 will be described with reference to FIGS.

In the example described below, the base unit 4 is configured using an SOI (Siliconon Insulator) wafer 100 as a material. As shown in FIG. 3, the SOI wafer 100 has a BOX layer (oxide film) 103 formed between a front surface side Si layer 101 and a back surface side Si layer 102.

First, as shown in FIG. 4, a resist 104 corresponding to the shape of the deformation suppressing portion 43 is laminated on the back surface Si layer 102 by patterning. Next, as shown in FIG. 5, the back-side Si layer 102 is etched. At this time, Si is selectively removed and the oxide film is not removed. Further, the BOX layer 103 is etched as shown in FIG. At this time, the oxide film is selectively removed and Si is not removed.

As shown in FIG. 7, by removing the resist 104, the formation of the deformation suppressing portion 43 is completed. That is, the portion of the back-side Si layer 102 and the BOX layer 103 that is not removed by etching becomes the deformation suppressing portion 43.

Details of the deformation of the base portion 4 on which the deformation suppressing portion 43 as described above is formed will be described below. As described above, if the base body 41 is bent and deformed by the vibration of the driving element 5, this deformation is transmitted and the reflecting plate 2 rotates. However, the drive element 5 also generates a force that causes the plate-like base portion main body 41 to be deformed so as not to contribute to the rotation of the reflection plate 2.

In particular, when a force that causes the base portion main body 41 to bend and deform in the X direction (that is, a deformation in which the central portion of the base portion main body 41 in the X direction is bent with respect to the end) is generated by the drive element 5, The force not only does not contribute to the rotation of the reflecting plate 2 but also inhibits the deformation of the base portion main body 41 that contributes to the rotation of the reflecting plate 2. That is, the deformation that causes the base portion main body 41 to bend in the Y direction (that is, the deformation in which the beam-

like portions

42A and 42B of the base portion main body 41 are warped with respect to the frame 6 side) causes the reflector 2 to rotate. This is a deformation (positive deformation) for moving the base part main body 41 so that the base part body 41 bends in the X direction (that is, a deformation in which the center part of the base part body 41 in the X direction is bent with respect to the end part). Inhibiting deformation that inhibits positive deformation.

In the present embodiment, the base main body 41 is formed with the deformation suppressing portion 43, so that normal deformation is likely to occur, but inhibition deformation is suppressed from occurring in the base main body 41. In this way, the deformation suppression unit 43 suppresses the inhibition deformation.

With the above configuration, the base portion 4 has the deformation suppressing portion 43, so that obstructive deformation that inhibits the positive deformation of the base portion 4 is suppressed, and the base portion 4 can be easily positively deformed by the driving element 5, and the reflector plate. 2 can be increased.

Further, since the deformation suppressing portion 43 extends along the X direction that is the axial direction of the rotation axis O, the obstructive deformation can be suppressed, and the swing angle of the reflecting plate 2 can be increased.

Moreover, the deformation | transformation suppression part 43 can be efficiently suppressed because the deformation | transformation suppression part 43 is arrange | positioned at the base part main body 41 by which the drive element 5 is arrange | positioned among the base parts 4. FIG.

Further, since the deformation suppressing portion 43 is disposed on the surface of the base portion 4 opposite to the surface on which the driving element 5 is disposed, the deformation suppressing portion 43 is disposed when the driving element 5 is disposed on the base portion 4. Interference with 43 can be suppressed.

Moreover, the deformation | transformation suppression part 43 can be efficiently suppressed by arrange | positioning in the position which overlaps with the drive element 5 in a Z direction.

In addition, since the deformation suppressing portion 43 has one surface of the base portion 4 formed in a convex shape, the deformation suppressing portion 43 can be formed by removing one surface of the plate-like member such as the SOI wafer 100. And the number of parts can be reduced.

In addition, this invention is not limited to the said Example, The other deformation | transformation etc. which can achieve the objective of this invention are included, and the following modifications etc. are also contained in this invention.

For example, in the said Example, although the base part 4 shall have the deformation | transformation suppression part 43 arrange | positioned at the base part main body 41, as shown in FIG. 8, it arrange | positioned at each of beam-

like part

42A, 42B. It is good also as a structure which further has the deformation | transformation suppression parts 44A and 44B. These deformation suppressing portions 44A and 44B may be any member that extends along the X direction and has one surface of the base portion 4 formed in a convex shape, similarly to the deformation suppressing portion 43, for example. In the illustrated example, the deformation suppressing portions 44A and 44B are arranged on the extension line (on the rotation shaft) of the

shaft portions

3A and 3B, but are not limited to such an arrangement. Thereby, it can suppress that obstructive deformation arises in beam-

like part

42A, 42B. In addition, the base part may have only the deformation | transformation suppression part arrange | positioned at the beam-shaped part.

Moreover, in the said Example, although the base part main body 41 shall be rectangular shape, as shown in FIG. 9, you may form the notch 40 so that the base part main body 41B may not interfere with the reflecting plate 2. FIG. . The notch 40 is formed on the side of the base portion main body 41 B opposite to the fixed side with respect to the frame 6, and has an arc shape along the outer peripheral edge of the circular reflector 2. In such a base portion main body 41B, in addition to the deformation suppressing portion 43 extending across both ends in the X direction, a pair of

deformation suppressing portions

45A and 45B arranged so as to sandwich the notch 40 in the X direction are further formed. May be.

Moreover, in the said Example, although the base part 4 and the drive element 5 shall be provided in the Y direction one side with respect to the reflecting plate 2, as shown to FIG. The base portion 4 and the drive element 5 may be provided on both sides in the direction.

Further, the base portion may not be supported by the frame at the side (side away from the reflector) extending along the X direction in the base portion main body. For example, as shown in FIGS. 12 and 13, the base portion 4B may be supported on the frame 6 by

arm portions

46A and 46B extending along the X direction while supporting the

shaft portions

3A and 3B.

Moreover, in the said Example, although the deformation | transformation suppression part 43 shall extend along the X direction which is an axial direction of the rotating shaft O, a deformation | transformation suppression part has some inclination with respect to the X direction. May extend.

Moreover, in the said Example, although the deformation | transformation suppression part 43 extended over the both ends of the X direction of the base part main body 41, for example, a deformation | transformation suppression part exists in the X direction both ends vicinity of the base part main body 41, for example. It may not be provided.

Moreover, in the said Example, although the deformation | transformation suppression part 43 shall be arrange | positioned on the surface on the opposite side to the surface where the drive element 5 in the base part 4 is arrange | positioned, for example, a deformation | transformation suppression part and the drive element 5 are arranged. When arranged at a position that does not interfere (for example, a position that does not correspond to the base portion main body 41 of the base portion 4 such as the beam-

like portions

42A and 42B), the deformation suppressing portion and the drive element are on the same side of the base portion. It may be arranged on the surface.

Moreover, in the said Example, although the deformation | transformation suppression part 43 shall be arrange | positioned in the position which overlaps with the drive element 5 in a Z direction, for example, when a deformation | transformation suppression part is arrange | positioned at beam-

like part

42A, 42B, The deformation suppression unit may be disposed at a position that does not overlap the drive element 5 in the Z direction.

In the above-described embodiment, the deformation suppressing portion 43 is formed so that one surface of the base portion 4 is formed in a convex shape, but may be formed in a concave shape. In addition, the deformation suppressing unit may be configured such that convex portions extending along the X direction and concave portions extending along the X direction are alternately arranged in the Y direction. Moreover, the deformation | transformation suppression part may be formed separately from the plate-shaped member which comprises a base part. For example, it is good also as a structure by which a deformation | transformation suppression part is joined to a plate-shaped member by plasma joining, or is adhere | attached. With such a configuration, the material of the plate-like member and the deformation suppressing portion can be appropriately selected.

In addition, the best configuration and method for carrying out the present invention have been disclosed in the above description, but the present invention is not limited to this. That is, although the present invention has been particularly illustrated and described with respect to particular embodiments, it will be understood that the present invention is not limited in shape to the embodiments described above without departing from the scope and spirit of the invention. Various modifications can be made by those skilled in the art in terms of materials, quantity, and other detailed configurations. Therefore, the description limiting the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such is included in this invention.

DESCRIPTION OF SYMBOLS 1 Optical deflector 2

Reflector

3A, 3B Axis part 4 Base part 41 Base part

main body

42A, 42B Beam-like part 43 Deformation suppression part 5 Drive element O Rotation axis

Claims

A reflector,
A pair of shafts that define the pivot axis of the reflector;
A base portion supporting the pair of shaft portions;
A driving element that rotates the reflecting plate by deforming the base portion,
The said base part has a deformation | transformation suppression part which suppresses the inhibition deformation | transformation used as inhibition of the deformation | transformation of the said base part for rotating the said reflecting plate, The optical deflector characterized by the above-mentioned.
2. The optical deflector according to claim 1, wherein the deformation suppressing portion extends along an axial direction of the rotation shaft.
The base portion is arranged in parallel with the reflecting plate at a position separated from the rotating shaft in the intersecting direction, and a base portion main body on which the driving element is disposed, and the base portion main body in the intersecting direction. A pair of beam-like portions that support the shaft portion by extending along,
2. The optical deflector according to claim 1, wherein the base portion includes the deformation suppressing portion arranged on the base portion main body. 3.
The base portion is juxtaposed in a direction intersecting the rotating shaft with respect to the reflecting plate, and extends along the intersecting direction from the base portion main body on which the driving element is disposed. And a pair of beam-like portions that support the shaft portion,
The optical deflector according to claim 1, wherein the base portion includes the deformation suppressing portion disposed on the beam-shaped portion.
The said base part is formed in plate shape, and has what was arrange | positioned as the said deformation | transformation suppression part in the surface on the opposite side to the surface where the said drive element is arrange | positioned. Light deflector.
6. The optical deflector according to claim 5, wherein the base portion has the deformation suppressing portion arranged at a position overlapping the driving element in the thickness direction thereof.
The optical deflector according to claim 1, wherein the base portion has one surface formed as a convex shape or a concave shape as the deformation suppressing portion.
2. The optical deflector according to claim 1, wherein the base part has a member formed separately from the plate-like member constituting the base part as the deformation suppressing part.