Patent Description:
As a MEMS, there is known a mirror device including a support portion, a movable portion provided with a mirror unit, and a pair of torsion bars connecting the movable portion to the support portion so that the movable portion is swingable around a predetermined axis as a center line. In such a mirror device, in order to suppress the mirror unit from being bent when the movable portion is swung at a high speed (for example, a resonance frequency level of the movable portion (several KHz to several tens KHz)), there is a case in which the mirror unit in the movable portion is connected to a frame-shaped frame through a pair of connection portions disposed on the axis (for example, see <CIT>).

<CIT> discloses electro-mechanical designs for MEMS scanning mirrors. In various embodiments, a driving coil may be situated on a reflective portion of a MEMS mirror. In some embodiments, a sensing coil may be situated partially or entirely on an outer frame portion of the MEMS mirror. However, <CIT> does at least not disclose the feature that an outer edge of the mirror unit and an inner edge of the frame are connected to each other so that a curvature in each of the pair of first connection regions is continuous when viewed from a direction perpendicular to the first axis and the second axis, and the feature that side surfaces on both sides of each of the pair of torsion bars and a side surface on an outside of the frame are connected to each other so that a curvature in each connection region is continuous when viewed from a direction perpendicular to the first axis and the second axis. <CIT> discloses a microelectromechanical system (MEMS) that includes a conductor with improved reliability. The conductor flexes with a moving member in the MEMS device, and the improved reliability is achieved through material selections that provides increased fatigue resistance, reduced crack propagation, and/or mechanisms for improved live at a given strain level. The conductor may include a single material, or may include layers of different materials. <CIT> discloses a torsion bar portion that is of a meandering shape including a plurality of straight sections and a plurality of turnover sections. The plurality of straight sections extends in a first direction along a swing axis and is juxtaposed in a second direction intersecting with the first direction. The plurality of turnover sections alternately couples two ends of the straight sections. Wiring is disposed on the torsion bar portion. The wiring includes first wiring sections and second wiring sections. The first wiring sections include damascene wiring sections that are disposed so as to be embedded in grooves formed in the turnover sections and that are made of a first metal material including Cu. The second wiring sections are disposed on the straight sections and are made of a second metal material more resistant to plastic deformation than the first metal material. However, <CIT> does at least not disclose the specific connection between the frame and the mirror unit as defined in claim <NUM> of the present application, and the feature that an outer edge of the mirror unit and an inner edge of the frame are connected to each other so that a curvature in each of the pair of first connection regions is continuous when viewed from a direction perpendicular to the first axis and the second axis. <CIT> discloses a MEMS mirror wherein a corner in a connecting area is rounded off to reduce stress concentration. <CIT> discloses a mirror comprising a movable plate. Corners are rounded for preventing stress concentration. <CIT> discloses a mirror comprising a torsion bar with rounded corners for removing stress concentration.

In the above-described mirror device, since the pair of torsion bars and the pair of connection portions are disposed on the same axis, stress occurring in the pair of connection portions due to the twist of the pair of torsion bars increases when the movable portion is swung at a high speed. Accordingly, there is concern that the movable portion may be damaged in the connection portion.

An object of the present disclosure is to provide a mirror device capable of suppressing both bending of a mirror unit and damage of a movable portion.

A mirror device of an aspect of the present disclosure includes: a support portion; a movable portion; and a pair of torsion bars disposed on both sides of the movable portion on a first axis and connecting the movable portion to the support portion so that the movable portion is swingable around the first axis as a center line, in which the movable portion includes a frame-shaped frame connected to the pair of torsion bars and a mirror unit disposed inside the frame, in which the mirror unit is connected to the frame in each of a pair of first connection regions located on both sides of the mirror unit in a direction parallel to a second axis perpendicular to the first axis, in which a region other than the pair of first connection regions in a region between the mirror unit and the frame is a space, in which an outer edge of the mirror unit and an inner edge of the frame are connected to each other so that a curvature in each of the pair of first connection regions is continuous when viewed from a direction perpendicular to the first axis and the second axis, and in which side surfaces on both sides of each of the pair of torsion bars and a side surface on an outside of the frame are connected to each other so that a curvature in each connection region is continuous when viewed from a direction perpendicular to the first axis and the second axis.

In the mirror device, the pair of torsion bars connected to the frame-shaped frame is disposed on the first axis and the pair of first connection regions in which the mirror unit and the frame-shaped frame are connected to each other is located on both sides of the mirror unit in a direction parallel to the second axis perpendicular to the first axis. Accordingly, even when the movable portion is swung at a high speed, stress occurring in each of the pair of first connection regions due to the twist of the pair of torsion bars becomes smaller than, for example, a case in which only the pair of connection regions is located on the first axis or a case in which the mirror unit and the frame-shaped frame are connected to each other only in one connection region. Furthermore, in the mirror device, the outer edge of the mirror unit and the inner edge of the frame are connected to each other so that the curvature in each of the pair of first connection regions is continuous when viewed from a direction perpendicular to the first axis and the second axis. Accordingly, stress concentration hardly occurs in each of the pair of first connection regions. As described above, according to the mirror device, both the bending of the mirror unit and the damage of the movable portion can be suppressed.

A mirror device of an aspect of the present disclosure includes: a support portion; a movable portion; and a pair of torsion bars disposed on both sides of the movable portion on a first axis and connecting the movable portion to the support portion so that the movable portion is swingable around the first axis as a center line, in which the movable portion includes a frame-shaped frame connected to the pair of torsion bars and a mirror unit disposed inside the frame, in which the mirror unit is connected to the frame in each of a pair of first connection regions located on both sides of the mirror unit in a direction parallel to a second axis perpendicular to the first axis and each of a pair of second connection regions located on both sides of the mirror unit in a direction parallel to the first axis, in which a region other than the pair of first connection regions and the pair of second connection regions in a region between the mirror unit and the frame is a space, in which an outer edge of the mirror unit and an inner edge of the frame are connected to each other so that a curvature in each of the pair of first connection regions is continuous when viewed from a direction perpendicular to the first axis and the second axis, and in which side surfaces on both sides of each of the pair of torsion bars and a side surface on an outside of the frame are connected to each other so that a curvature in each connection region is continuous when viewed from a direction perpendicular to the first axis and the second axis.

In the mirror device, the pair of torsion bars connected to the frame-shaped frame is disposed on the first axis and the pair of first connection regions in which the mirror unit and the frame-shaped frame are connected to each other is located on both sides of the mirror unit in a direction parallel to the second axis perpendicular to the first axis. Furthermore, the pair of second connection regions in which the mirror unit and the frame-shaped frame are connected to each other is located on both sides of the mirror unit in a direction parallel to the first axis. Accordingly, even when the movable portion is swung at a high speed, stress occurring in each of the pair of first connection regions and the pair of second connection regions due to the twist of the pair of torsion bars becomes smaller than, for example, a case in which only the pair of connection regions is located on the first axis or a case in which the mirror unit and the frame-shaped frame are connected to each other only in one connection region. Furthermore, in the mirror device, the outer edge of the mirror unit and the inner edge of the frame are connected to each other so that the curvature in each of the pair of first connection regions is continuous when viewed from a direction perpendicular to the first axis and the second axis. Accordingly, stress concentration hardly occurs in each of the pair of first connection regions. As described above, according to the mirror device, both the bending of the mirror unit and the damage of the movable portion can be suppressed.

In the mirror device of an aspect of the present disclosure, the outer edge of the mirror unit and the inner edge of the frame may be connected to each other so that a curvature in each of the pair of second connection regions is continuous when viewed from a direction perpendicular to the first axis and the second axis. Accordingly, stress concentration hardly occurs in each of the pair of second connection regions.

In the mirror device of an aspect of the present disclosure, the pair of second connection regions may be located on both sides of the mirror unit on the first axis. Accordingly, the inertia moment of the movable portion around the first axis can be decreased.

In the mirror device of an aspect of the present disclosure, the pair of first connection regions may be located on both sides of the mirror unit on the second axis. Accordingly, a sufficient distance between each of the pair of torsion bars and each of the pair of first connection regions (a distance that the influence of the twist of the pair of torsion bars hardly reaches each of the pair of first connection regions) can be secured. Thus, both the bending of the mirror unit and the damage of the movable portion can be suppressed while simplifying the configuration of the movable portion.

In the mirror device of an aspect of the present disclosure, the frame may include a pair of first portions connected to the mirror unit and extending in a direction parallel to the first axis and a width of each of the pair of first portions in a direction parallel to the second axis may become smaller as it goes away from each of the pair of first connection region. Accordingly, stress due to the twist of the pair of torsion bars is dispersed in the portion of which the width is smaller than that of each of the pair of first portions so that stress occurring in each of the pair of first connection regions can be further decreased. Furthermore, it is possible to decrease the inertia moment of the movable portion as the width of each of the pair of first portions decreases while securing the connection strength of each of the pair of first connection regions. It is advantageous to decrease the inertia moment of the movable portion when swinging the movable portion at a high speed.

In the mirror device of an aspect of the present disclosure, the frame may further include a pair of second portions connected to the pair of torsion bars and extending in a direction parallel to the second axis. Accordingly, stress due to the twist of the pair of torsion bars is dispersed in the portion between the first portion and the second portion connected or coupled to each other so that stress occurring in each of the pair of first connection regions can be further decreased.

In the mirror device of an aspect of the present disclosure, an inner edge of each of the pair of first portions and an inner edge of each of the pair of second portions may be connected to each other so that a curvature in each of a plurality of connection regions is continuous when viewed from a direction perpendicular to the first axis and the second axis. Accordingly, the occurrence of stress concentration can be suppressed in each of the plurality of connection regions in which the inner edge of each of the pair of first portions and the inner edge of each of the pair of second portions are connected to each other.

In the mirror device of an aspect of the present disclosure, an outer edge of each of the pair of first portions and an outer edge of each of the pair of second portions may be connected to each other so that a curvature in each of a plurality of connection regions is continuous when viewed from a direction perpendicular to the first axis and the second axis. Accordingly, the occurrence of stress concentration can be suppressed in each of the plurality of connection regions in which the outer edge of each of the pair of first portions and the outer edge of each of the pair of second portions are connected to each other.

In the mirror device of an aspect of the present disclosure, a length of each of the pair of first portions in a direction parallel to the first axis may be longer than a length of each of the pair of second portions in a direction parallel to the second axis. Accordingly, a sufficient distance between each of the pair of torsion bars and each of the pair of first connection regions (a distance that the influence of the twist of the pair of torsion bars hardly reaches each of the pair of first connection regions) can be secured while suppressing an increase in the inertia moment of the movable portion.

In the mirror device of an aspect of the present disclosure, a distance between each of the pair of first connection regions and one of the pair of second portions and a distance between each of the pair of first connection regions and the other of the pair of second portions may be longer than a distance between the first axis and each of the pair of first portions. Accordingly, a sufficient distance between each of the pair of torsion bars and each of the pair of first connection regions (a distance that the influence of the twist of the pair of torsion bars hardly reaches each of the pair of first connection regions) can be secured while suppressing an increase in the inertia moment of the movable portion.

In the mirror device of an aspect of the present disclosure, a shape of the mirror unit when viewed from a direction perpendicular to the first axis and the second axis may be an ellipse having a major axis along the first axis. Accordingly, a sufficient area of the mirror surface can be secured while suppressing an increase in the inertia moment of the movable portion.

In the mirror device of an aspect of the present disclosure, a width of each of the pair of first connection regions in a direction parallel to the first axis may be <NUM>% or less of a width of the mirror unit in a direction parallel to the first axis. Accordingly, it is possible to secure a sufficient connection strength between the mirror unit and the frame and a sufficient distance between each of the pair of torsion bars and each of the pair of first connection regions at the same time.

According to the present disclosure, it is possible to provide a mirror device capable of suppressing both bending of a mirror unit and damage of a movable portion.

Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. Additionally, in the drawings, the same reference numerals will be given to the same or equivalent parts and a redundant description will be omitted.

As illustrated in <FIG>, a mirror device <NUM> includes a base <NUM>, a support portion <NUM>, a movable portion <NUM>, a pair of torsion bars <NUM> and <NUM>, a pair of torsion bars <NUM> and <NUM>, and a magnetic field generator <NUM>. The base <NUM>, the support portion <NUM>, the movable portion <NUM>, the pair of torsion bars <NUM> and <NUM>, and the pair of torsion bars <NUM> and <NUM> are integrally formed by a Silicon on Insulator (SOI) substrate. That is, the mirror device <NUM> is configured as a MEMS device. The magnetic field generator <NUM> is configured by, for example, a permanent magnet having a Halbach array. In the mirror device <NUM>, the movable portion <NUM> provided with a mirror unit <NUM> is swung around each of an X axis (a first axis) and a Y axis (a second axis perpendicular to the first axis) as a center line. The mirror device <NUM> is used for, for example, an optical switch for optical communication, an optical scanner, and the like.

The base <NUM> has, for example, a rectangular outer shape when viewed from a direction perpendicular to the X axis and the Y axis and is formed in a frame shape. The base <NUM> is disposed at one side of the magnetic field generator <NUM>. The support portion <NUM> has, for example, an octagonal outer shape when viewed from a direction perpendicular to the X axis and the Y axis and is formed in a frame shape. The support portion <NUM> is disposed inside the base <NUM> while being separated from the magnetic field generator <NUM>. The movable portion <NUM> has, for example, a rectangular outer shape when viewed from a direction perpendicular to the X axis and the Y axis. The movable portion <NUM> is disposed inside the support portion <NUM> while being separated from the magnetic field generator <NUM>.

The pair of torsion bars <NUM> and <NUM> is disposed on both sides of the support portion <NUM> on the Y axis. The pair of torsion bars <NUM> and <NUM> connects the support portion <NUM> to the base <NUM> so that the support portion <NUM> is swingable around the Y axis as a center line. Each of the torsion bars <NUM> and <NUM> extends in a meandering shape in order to improve strength and easily adjust a torsion spring constant. The pair of torsion bars <NUM> and <NUM> is disposed on both sides of the movable portion <NUM> on the X axis. The pair of torsion bars <NUM> and <NUM> connects the movable portion <NUM> to the support portion <NUM> so that the movable portion <NUM> is swingable around the X axis as a center line. Each of the torsion bars <NUM> and <NUM> extends in a linear shape along the X axis.

The mirror device <NUM> further includes a coil <NUM>, a coil <NUM>, a plurality of wires <NUM>, <NUM>, <NUM>, and <NUM>, and a plurality of electrode pads <NUM>, <NUM>, <NUM>, and <NUM>. The coil <NUM> is provided in the support portion <NUM>. The coil <NUM> extends in, for example, a spiral shape while being embedded in the support portion <NUM>. The coil <NUM> is provided in the movable portion <NUM>. The coil <NUM> extends in, for example, a spiral shape while being embedded in the movable portion <NUM>. Each of the coils <NUM> and <NUM> is formed of, for example, a metal material such as copper. Additionally, in the drawings, a region in which each of the coils <NUM> and <NUM> is disposed is indicated by hatching.

The plurality of electrode pads <NUM>, <NUM>, <NUM>, and <NUM> are provided in the base <NUM>. Each of the electrode pads <NUM>, <NUM>, <NUM>, and <NUM> is exposed from the insulation layer <NUM> in the base <NUM> to the outside. The insulation layer <NUM> is integrally formed so as to cover the surfaces of the base <NUM>, the support portion <NUM>, the movable portion <NUM>, the pair of torsion bars <NUM> and <NUM>, and the pair of torsion bars <NUM> and <NUM> (the surfaces opposite to the magnetic field generator <NUM>). The insulation layer <NUM> is formed by, for example, a silicon dioxide film, a silicon nitride film, or the like.

The wire <NUM> electrically connects one end of the coil <NUM> to the electrode pad <NUM>. The wire <NUM> extends from one end of the coil <NUM> to the electrode pad <NUM> through the torsion bar <NUM> while being embedded in the insulation layer <NUM>. The wire <NUM> electrically connects the other end of the coil <NUM> to the electrode pad <NUM>. The wire <NUM> extends from the other end of the coil <NUM> to the electrode pad <NUM> through the torsion bar <NUM> while being embedded in the insulation layer <NUM>. Each of the wires <NUM> and <NUM> is formed of, for example, a metal material such as aluminum.

The wire <NUM> electrically connects one end of the coil <NUM> to the electrode pad <NUM>. The wire <NUM> extends from one end of the coil <NUM> to the electrode pad <NUM> through the torsion bar <NUM>, a part of the support portion <NUM>, and the torsion bar <NUM> while being embedded in the insulation layer <NUM>. The wire <NUM> electrically connects the other end of the coil <NUM> to the electrode pad <NUM>. The wire <NUM> extends from the other end of the coil <NUM> to the electrode pad <NUM> through the torsion bar <NUM>, a part of the support portion <NUM>, and the torsion bar <NUM> while being embedded in the insulation layer <NUM>. A portion passing through each of the torsion bars <NUM> and <NUM> in each of the wires <NUM> and <NUM> is formed of, for example, a metal material such as tungsten and the other portions are formed of a metal material such as aluminum. As will be described later, since torsion associated with the resonance of the movable portion <NUM> at the natural frequency occurs in the pair of torsion bars <NUM> and <NUM>, the load applied to the portion passing through each of the torsion bars <NUM> and <NUM> in each of the wires <NUM> and <NUM> is larger than that of the other portions. However, in the mirror device <NUM>, since the portion passing through each of the torsion bars <NUM> and <NUM> in each of the wires <NUM> and <NUM> is formed of a metal material having Vickers hardness larger than that of the other portions, metal fatigue hardly occurs in each of the wires <NUM> and <NUM> on each of the torsion bars <NUM> and <NUM>. Additionally, in the drawings, a portion passing through each of the torsion bars <NUM> and <NUM> in each of the wires <NUM> and <NUM> is indicated by hatching.

In the mirror device <NUM> with the above-described configuration, when a drive signal for a linear operation is input to the coil <NUM> through the electrode pads <NUM> and <NUM> and the wires <NUM> and <NUM>, a Lorentz force acts on the coil <NUM> by interaction with the magnetic field generated by the magnetic field generator <NUM>. By using a balance between the Lorentz force and the elastic force of the pair of torsion bars <NUM> and <NUM>, the mirror unit <NUM> can be operated linearly along with the support portion <NUM> while using the Y axis as a center line. Meanwhile, when a drive signal for a resonance operation is input to the coil <NUM> through the electrode pads <NUM> and <NUM> and the wires <NUM> and <NUM>, a Lorentz force acts on the coil <NUM> by interaction with the magnetic field generated by the magnetic field generator <NUM>. By using the resonance of the movable portion <NUM> at the natural frequency in addition to the Lorentz force, the mirror unit <NUM> can resonate while using the X axis as a center line. Additionally, the natural frequency is determined by the inertia moment of the movable portion <NUM>, the torsion spring constants of the pair of torsion bars <NUM> and <NUM>, or the like.

As illustrated in <FIG>, the movable portion <NUM> includes a frame-shaped frame <NUM> in addition to the mirror unit <NUM>. The pair of torsion bars <NUM> and <NUM> is connected to the frame <NUM>. The mirror unit <NUM> is disposed inside the frame <NUM>. The mirror unit <NUM> is connected to the frame <NUM> of each of a pair of connection regions (first connection regions) 40a and 40b located on both sides of the mirror unit <NUM> in a direction (hereinafter, referred to as a "Y-axis direction") parallel to the Y axis. More specifically, the mirror unit <NUM> is connected to the frame <NUM> of each of the pair of connection regions 40a and 40b located on both sides of the mirror unit <NUM> on the Y axis. A region other than the pair of connection regions 40a and 40b in a region between the mirror unit <NUM> and the frame <NUM> is a space. That is, the mirror unit <NUM> and the frame <NUM> are connected to each other only in the pair of connection regions 40a and 40b. A width (minimum width) W2 of each of the connection regions 40a and 40b in a direction (hereinafter, referred to as an "X-axis direction") parallel to the X axis is <NUM>% or less of a width (a maximum width) W1 of the mirror unit <NUM> in the X-axis direction.

The shape of the mirror unit <NUM> when viewed from a direction perpendicular to the X axis and the Y axis is an ellipse having a major axis along the X axis and a minor axis along the Y axis centered at the intersection O between the X axis and the Y axis. A mirror surface 41a is formed on the surface of the mirror unit <NUM> (the surface opposite to the magnetic field generator <NUM>) by, for example, a metal film formed of aluminum or the like.

The frame <NUM> has, for example, a rectangular outer shape when viewed from a direction perpendicular to the X axis and the Y axis and is formed in a frame shape. More specifically, the frame <NUM> is formed in a frame shape by a pair of first portions <NUM> and <NUM> extending in the X-axis direction and a pair of second portions <NUM> and <NUM> extending in the Y-axis direction. The length of each of the first portions <NUM> and <NUM> in the X-axis direction is longer than the length of each of the second portions <NUM> and <NUM> in the Y-axis direction. Additionally, the length of each of the first portions <NUM> and <NUM> in the X-axis direction can be regarded as the length of the outer edge or the inner edge of each of the first portions <NUM> and <NUM> when viewed from a direction perpendicular to the X axis and the Y axis. The length of each of the second portions <NUM> and <NUM> in the Y-axis direction can be regarded as the length of the outer edge or the inner edge of each of the second portions <NUM> and <NUM> when viewed from a direction perpendicular to the X axis and the Y axis.

Each of the distance between the connection region 40a and the second portion <NUM>, the distance between the connection region 40a and the second portion <NUM>, the distance between the connection region 40b and the second portion <NUM>, and the distance between the connection region 40b and the second portion <NUM> is longer than each of the distance between the X axis and the first portion <NUM> and the distance between the X axis and the first portion <NUM>. Additionally, the distance between the connection region 40a and the second portion <NUM> can be regarded as the distance (the maximum distance) from the outer edge on the side of the second portion <NUM> in the connection region 40a to the inner edge of the second portion <NUM> in the X-axis direction. The distance between the connection region 40a and the second portion <NUM> can be regarded as the distance (the maximum distance) from the outer edge on the side of the second portion <NUM> in the connection region 40a to the inner edge of the second portion <NUM> in the X-axis direction. The distance between the connection region 40b and the second portion <NUM> can be regarded as the distance (the maximum distance) from the outer edge on the side of the second portion <NUM> in the connection region 40b to the inner edge of the second portion <NUM> in the X-axis direction. The distance between the connection region 40b and the second portion <NUM> can be regarded as the distance (the maximum distance) from the outer edge on the side of the second portion <NUM> in the connection region 40b to the inner edge of the second portion <NUM> in the X-axis direction. The distance between the X axis and the first portion <NUM> can be regarded as the distance (the maximum distance) from the X axis to the inner edge of the first portion <NUM> in the Y-axis direction. The distance between the X axis and the first portion <NUM> can be regarded as the distance (the maximum distance) from the X axis to the inner edge of the first portion <NUM> in the Y-axis direction.

The mirror unit <NUM> is connected to a side surface 43a on the inside (the side of the mirror unit <NUM>) of the first portion <NUM> and a side surface 44a on the inside (the side of the mirror unit <NUM>) of the first portion <NUM>. The torsion bar <NUM> is connected to a side surface 45b on the outside (the side opposite to the mirror unit <NUM>) of the second portion <NUM>. The torsion bar <NUM> is connected to a side surface 46b on the outside (the side opposite to the mirror unit <NUM>) of the second portion <NUM>.

A side surface 41b of the mirror unit <NUM> and the side surface 43a on the inside of the first portion <NUM> are connected to each other so that the curvature in the connection region 40a is continuous. The side surface 41b of the mirror unit <NUM> and the side surface 44a on the inside of the first portion <NUM> are connected to each other so that the curvature in the connection region 40b is continuous. That is, the outer edge of the mirror unit <NUM> and the inner edge of the frame <NUM> are connected to each other so that the curvature in each of the connection regions 40a and 40b is continuous when viewed from a direction perpendicular to the X axis and the Y axis. Additionally, the "connection with the continuous curvature" means the connection without any point (for example, an apex of a sharp corner (including acute, right, and obtuse angles)) in which the curvature is not continuous. Thus, when there is not any point that the curvature is not continuous, a linear portion may be included in the outer edge of the mirror unit <NUM> and the inner edge of the frame <NUM> in each of the connection regions 40a and 40b (the value of the curvature of the linear portion can be regarded as zero).

The width of the first portion <NUM> in the Y-axis direction becomes smaller as it goes closer to the torsion bar <NUM> from the connection region 40a in the X-axis direction and as it goes closer to the torsion bar <NUM> from the connection region 40a in the X-axis direction. That is, the width of the first portion <NUM> in the Y-axis direction becomes smaller as it goes away from the connection region 40a. Here, a side surface 43b on the outside (the side opposite to the mirror unit <NUM>) of the first portion <NUM> becomes a flat surface parallel to the X axis and the side surface 43a on the inside of the first portion <NUM> becomes a curved surface curved in a concave shape toward the side opposite to the mirror unit <NUM> so as to be closer to the side surface 43b as it goes away from the connection region 40a. The width of the first portion <NUM> in the Y-axis direction becomes smaller as it goes closer to the torsion bar <NUM> from the connection region 40b in the X-axis direction and as it goes closer to the torsion bar <NUM> from the connection region 40b in the X-axis direction. That is, the width of the first portion <NUM> in the Y-axis direction becomes smaller as it goes away from the connection region 40b. Here, a side surface 44b on the outside (the side opposite to the mirror unit <NUM>) of the first portion <NUM> becomes a flat surface parallel to the X axis and the side surface 44a on the inside of the first portion <NUM> becomes a curved surface curved in a concave shape toward the side opposite to the mirror unit <NUM> so as to be closer to the side surface 44b as it goes away from the connection region 40b.

The side surface 43a on the inside of the first portion <NUM> and a side surface 45a on the inside (the side of the mirror unit <NUM>) of the second portion <NUM> are connected to each other so that the curvature in the connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. The side surface 43a on the inside of the first portion <NUM> and a side surface 46a on the inside (the side of the mirror unit <NUM>) in the second portion <NUM> are connected to each other so that the curvature in the connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. The side surface 44a on the inside of the first portion <NUM> and the side surface 45a on the inside of the second portion <NUM> are connected to each other so that the curvature in the connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. The side surface 44a on the inside of the first portion <NUM> and the side surface 46a on the inside of the second portion <NUM> are connected to each other so that the curvature in the connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. That is, the inner edge of each of the first portions <NUM> and <NUM> and the inner edge of each of the second portions <NUM> and <NUM> are connected to each other so that the curvature in each connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis.

The side surface 43b on the outside of the first portion <NUM> and the side surface 45b on the outside of the second portion <NUM> are connected to each other so that the curvature in the connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. The side surface 43b on the outside of the first portion <NUM> and the side surface 46b on the outside of the second portion <NUM> are connected to each other so that the curvature in the connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. The side surface 44b on the outside of the first portion <NUM> and the side surface 45b on the outside of the second portion <NUM> are connected to each other so that the curvature in the connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. The side surface 44b on the outside of the first portion <NUM> and the side surface 46b on the outside of the second portion <NUM> are connected to each other so that the curvature in the connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. That is, the outer edge of each of the first portions <NUM> and <NUM> and the outer edge of each of the second portions <NUM> and <NUM> are connected to each other so that the curvature in each connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis.

The second portion <NUM> is provided with a slit 45c which extends in the Y-axis direction. The slit 45c is located between the torsion bar <NUM> and the mirror unit <NUM> when viewed from a direction perpendicular to the X axis and the Y axis. The second portion <NUM> is provided with a slit 46c which extends in the Y-axis direction. The slit 46c is located between the torsion bar <NUM> and the mirror unit <NUM> when viewed from a direction perpendicular to the X axis and the Y axis.

The coil <NUM> extends along each of the side surfaces 43b and 44b on the outside of the first portions <NUM> and <NUM>. The center position of the extension region of the coil <NUM> in the first portion <NUM> (the center position of the width in the Y-axis direction) is located on the outside (the side opposite to the connection region 40a) in relation to the center position of the first portion <NUM> (the center position of the width in the Y-axis direction). The center position of the extension region of the coil <NUM> in the first portion <NUM> (the center position of the width in the Y-axis direction) is located on the outside (the side opposite to the connection region 40b) in relation to the center position of the first portion <NUM> (the center position of the width in the Y-axis direction).

The coil <NUM> extends along each of the side surfaces 45a and 46a on the inside of the second portions <NUM> and <NUM>. The center position of the extension region of the coil <NUM> in the second portion <NUM> (the center position of the width in the X-axis direction) is located on the inside (the side opposite to the torsion bar <NUM>) (here, the inside in relation to the slit 45c) in relation to the center position of the second portion <NUM> (the center position of the width in the X-axis direction). The center position of the extension region of the coil <NUM> in the second portion <NUM> (the center position of the width in the X-axis direction) is located on the inside (the side opposite to the torsion bar <NUM>) (here, the inside in relation to the slit 46c) in relation to the center position of the second portion <NUM> (the center position of the width in the X-axis direction).

As illustrated in <FIG>, the side surfaces 7a on both sides of the torsion bar <NUM> and the side surface 45b on the outside of the second portion <NUM> are connected to each other so that the curvature in each connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. That is, the outer edge of the torsion bar <NUM> and the outer edge of the second portion <NUM> are connected to each other so that the curvature in each connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. The side surfaces 7a on both sides of the torsion bar <NUM> and the side surface 3a on the inside (the side of the mirror unit <NUM>) of the support portion <NUM> are connected to each other so that the curvature is continuous when viewed from a direction perpendicular to the X axis and the Y axis. That is, the outer edge of the torsion bar <NUM> and the inner edge of the support portion <NUM> are connected to each other so that the curvature in each connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. The curvature of the outer edge of the torsion bar <NUM> in a region connected to the outer edge of the second portion <NUM> is smaller than the curvature of the outer edge of the torsion bar <NUM> in a region connected to the inner edge of the support portion <NUM>.

Similarly, the side surfaces on both sides of the torsion bar <NUM> and the side surface 46b on the outside of the second portion <NUM> are connected to each other so that the curvature in each connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis (see <FIG> and <FIG>). That is, the outer edge of the torsion bar <NUM> and the outer edge of the second portion <NUM> are connected to each other so that the curvature in each connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. The side surfaces on both sides of the torsion bar <NUM> and the side surface 3a on the inside of the support portion <NUM> are connected to each other so that the curvature in each connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis (see <FIG> and <FIG>). That is, the outer edge of the torsion bar <NUM> and the inner edge of the support portion <NUM> are connected to each other so that the curvature in each connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. The curvature of the outer edge of the torsion bar <NUM> in a region connected to the outer edge of the second portion <NUM> is smaller than the curvature of the outer edge of the torsion bar <NUM> in a region connected to the inner edge of the support portion <NUM> (see <FIG> and <FIG>).

As illustrated in <FIG>, the coil <NUM> extends along the side surface 3b on the outside (the side opposite to the mirror unit <NUM>) of the support portion <NUM>. The center position (the center position of the width in the X-axis direction) of the extension region of the coil <NUM> in the portion connected to the torsion bar <NUM> in the support portion <NUM> is located on the outside (the side opposite to the torsion bar <NUM>) in relation to the center position (the center position of the width in the X-axis direction) of the corresponding portion. The center position (the center position of the width in the X-axis direction) of the extension region of the coil <NUM> in the portion connected to the torsion bar <NUM> in the support portion <NUM> is located on the outside (the side opposite to the torsion bar <NUM>) in relation to the center position (the center position of the width in the X-axis direction) of the corresponding portion (see <FIG> and <FIG>).

As illustrated in <FIG>, the back surface of the support portion <NUM> (the surface on the side of the magnetic field generator <NUM>) is provided with a beam structure <NUM>. The beam structure <NUM> extends in an annular shape along the frame-shaped support portion <NUM> when viewed from a direction perpendicular to the X axis and the Y axis. The width (the width in the X-axis direction) of the portion extending in the Y-axis direction in the beam structure <NUM> is smaller than the width (the width in the Y-axis direction) of the portion extending in the X-axis direction in the beam structure <NUM>. A plurality of punched portions 31a are formed in the portion extending in the X-axis direction in the beam structure <NUM> except for an intermediate portion crossing the Y axis. The size of each punched portion 31a increases as it goes away from the Y axis.

The center position (the center position of the width in the X-axis direction) of the extension portion in the Y-axis direction on the side of the torsion bar <NUM> in the beam structure <NUM> is located on the outside (the side opposite to the torsion bar <NUM>) in relation to the center position (the center position of the width in the X-axis direction) of the portion connected to the torsion bar <NUM> and extending in the Y-axis direction in the support portion <NUM>. The center position (the center position of the width in the X-axis direction) of the portion extending in the Y-axis direction on the side of the torsion bar <NUM> in the beam structure <NUM> is located on the outside (the side opposite to the torsion bar <NUM>) in relation to the center position (the center position of the width in the X-axis direction) of the portion connected to the torsion bar <NUM> and extending in the Y-axis direction in the support portion <NUM>.

The back surface of the mirror unit <NUM> (the surface on the side of the magnetic field generator <NUM>) is provided with a plurality of beam structures <NUM>, <NUM>, and <NUM>. A beam structure <NUM> extends from the intersection O in a V shape toward both edge portions of the connection region 40a in the X-axis direction when viewed from a direction perpendicular to the X axis and the Y axis. A beam structure <NUM> extends from the intersection O in a V shape toward both edge portions of the connection region 40b in the X-axis direction when viewed from a direction perpendicular to the X axis and the Y axis. A beam structure <NUM> extends from the intersection O in an X shape toward both edge portions in the X-axis direction when viewed from a direction perpendicular to the X axis and the Y axis.

In the mirror device <NUM>, the pair of torsion bars <NUM> and <NUM> connected to a frame-shaped frame <NUM> is disposed on the X axis and the pair of connection regions 40a and 40b in which the mirror unit <NUM> and the frame-shaped frame <NUM> are connected to each other is located on both sides of the mirror unit <NUM> in the Y-axis direction. Accordingly, even when the movable portion <NUM> is swung at a high speed while using the X axis as a center line, stress occurring in each of the connection regions 40a and 40b due to the twist of the pair of torsion bars <NUM> and <NUM> becomes smaller than, for example, a case in which only the pair of connection regions 40a and 40b is located on the X axis or a case in which the mirror unit <NUM> and the frame-shaped frame <NUM> are connected to each other only in one connection region 40a (or 40b). Further, in the mirror device <NUM>, the outer edge of the mirror unit <NUM> and the inner edge of the frame <NUM> are connected to each other so that the curvature in each of the connection regions 40a and 40b is continuous when viewed from a direction perpendicular to the X axis and the Y axis. Accordingly, stress concentration hardly occurs in each of the connection regions 40a and 40b. As described above, according to the mirror device <NUM>, both the bending of the mirror unit <NUM> and the damage of the movable portion <NUM> can be suppressed.

In the mirror device <NUM>, the pair of connection regions 40a and 40b is located on both sides of the mirror unit <NUM> on the Y axis. Accordingly, a sufficient distance between each of the torsion bars <NUM> and <NUM> and each of the connection regions 40a and 40b (a distance that the influence of the twist of the pair of torsion bars <NUM> and <NUM> hardly reaches each of the connection regions 40a and 40b) can be secured. Thus, both the bending of the mirror unit <NUM> and the damage of the movable portion <NUM> can be suppressed while simplifying the configuration of the movable portion <NUM>.

In the mirror device <NUM>, the frame <NUM> includes the pair of first portions <NUM> and <NUM> connected to the mirror unit <NUM> and extending in the X-axis direction and the width of each of the first portions <NUM> and <NUM> in the Y-axis direction becomes smaller as it goes away from each of the connection regions 40a and 40b. Accordingly, stress due to the twist of the pair of torsion bars <NUM> and <NUM> is dispersed in the portion of which the width is smaller than that of each of the first portions <NUM> and <NUM> so that stress occurring in each of the connection regions 40a and 40b can be further decreased. Furthermore, it is possible to decrease the inertia moment of the movable portion <NUM> when the X axis is a rotation axis as the width of each of the first portions <NUM> and <NUM> decreases while securing the connection strength in each of the connection regions 40a and 40b. It is advantageous to decrease the inertia moment of the movable portion <NUM> while using the X axis a rotation axis when swinging the movable portion <NUM> at a high speed while using the X axis as a center line. In particular, since the side surface 43a on the inside of the first portion <NUM> becomes a curved surface curved in a concave shape toward the side opposite to the mirror unit <NUM> so as to be closer to the side surface 43b on the outside of the first portion <NUM> as it goes away from the connection region 40a and the side surface 44a on the inside of the first portion <NUM> becomes a curved surface curved in a concave shape toward the side opposite to the mirror unit <NUM> so as to be closer to the side surface 44b on the outside of the first portion <NUM> as it goes away from the connection region 40b, stress due to the twist of the pair of torsion bars <NUM> and <NUM> is further dispersed so that the occurrence of stress concentration in each of the first portions <NUM> and <NUM> can be suppressed.

(a) of <FIG> is a plan view of the movable portion <NUM> of the comparative example and (b) of <FIG> is a plan view of the movable portion <NUM> (the above-described movable portion <NUM>) of the embodiment. (a) of <FIG> is a plan view of the movable portion <NUM> of the comparative example and (b) of <FIG> is a plan view of the movable portion <NUM> of the embodiment. In the movable portion <NUM> of the comparative example illustrated in (a) of <FIG>, the width of each of the first portions <NUM> and <NUM> in the Y-axis direction is constant and the width of the movable portion <NUM> in the Y-axis direction is the same as the width of the movable portion <NUM> of the embodiment illustrated in (b) of <FIG>. In the movable portion <NUM> of the comparative example illustrated in (a) of <FIG>, the width of each of the first portions <NUM> and <NUM> in the Y-axis direction is constant and the width of the movable portion <NUM> in the Y-axis direction is smaller than the width of the movable portion <NUM> of the embodiment illustrated in (b) of <FIG>.

When the movable portion <NUM> of the comparative example illustrated in (a) of <FIG> is compared with the movable portion <NUM> of the comparative example illustrated in (a) of <FIG>, the inertia moment of the movable portion <NUM> when the X axis is a rotation axis increases in the movable portion <NUM> of the comparative example illustrated in (a) of <FIG> and stress due to the twist of the pair of torsion bars <NUM> and <NUM> cannot be decreased in the movable portion <NUM> of the comparative example illustrated in (a) of <FIG>. On the other hand, according to the movable portion <NUM> of the embodiment illustrated in (b) of <FIG> and <FIG> of <FIG>, the inertia moment of the movable portion <NUM> when the X axis is a rotation axis can be smaller than the movable portion <NUM> of the comparative example illustrated in (a) of <FIG>. Further, according to the movable portion <NUM> of the embodiment illustrated in (b) of <FIG> and <FIG> of <FIG>, stress due to the twist of the pair of torsion bars <NUM> and <NUM> can be smaller than the movable portion <NUM> of the comparative example illustrated in (a) of <FIG>.

In the mirror device <NUM>, the frame <NUM> includes the pair of second portions <NUM> and <NUM> connected to the pair of torsion bars <NUM> and <NUM> and extending in the Y-axis direction in addition to the pair of first portions <NUM> and <NUM>. Accordingly, stress due to the twist of the pair of torsion bars <NUM> and <NUM> is dispersed in the portion between each of the first portions <NUM> and <NUM> and each of the second portions <NUM> and <NUM> connected to each other so that stress occurring in each of the connection regions 40a and 40b can be further decreased.

In the mirror device <NUM>, the inner edge of each of the first portions <NUM> and <NUM> and the inner edge of each of the second portions <NUM> and <NUM> are connected to each other so that the curvature in each connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. Accordingly, the occurrence of stress concentration can be suppressed in each connection region between the inner edge of each of the first portions <NUM> and <NUM> and the inner edge of each of the second portions <NUM> and <NUM>.

In the mirror device <NUM>, the outer edge of each of the first portions <NUM> and <NUM> and the outer edge of each of the second portions <NUM> and <NUM> are connected to each other so that the curvature in each connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. Accordingly, the occurrence of stress concentration can be suppressed in each connection region between the outer edge of each of the first portions <NUM> and <NUM> and the outer edge of each of the second portions <NUM> and <NUM>.

In the mirror device <NUM>, the length of each of the first portions <NUM> and <NUM> in the X-axis direction is longer than the length of each of the second portions <NUM> and <NUM> in the Y-axis direction. Accordingly, a sufficient distance between each of the torsion bars <NUM> and <NUM> and each of the connection regions 40a and 40b (a distance that the influence of the twist of the pair of torsion bars <NUM> and <NUM> hardly reaches each of the connection regions 40a and 40b) can be secured while suppressing an increase in the inertia moment of the movable portion <NUM> when the X axis is a rotation axis.

In the mirror device <NUM>, each of the distance between the connection region 40a and the second portion <NUM>, the distance between the connection region 40a and the second portion <NUM>, the distance between the connection region 40b and the second portion <NUM>, and the distance between the connection region 40b and the second portion <NUM> is longer than each of the distance between the X axis and the first portion <NUM> and the distance between the X axis and the first portion <NUM>. Accordingly, a sufficient distance between each of the torsion bars <NUM> and <NUM> and each of the connection regions 40a and 40b (a distance that the influence of the twist of the pair of torsion bars <NUM> and <NUM> hardly reaches each of the connection regions 40a and 40b) can be secured while suppressing an increase in the inertia moment of the movable portion <NUM> when the X axis is a rotation axis.

In the mirror device <NUM>, the shape of the mirror unit <NUM> when viewed from a direction perpendicular to the X axis and the Y axis is an ellipse having a major axis along the X axis. Accordingly, a sufficient area of the mirror surface 41a can be secured while suppressing an increase in the inertia moment of the movable portion <NUM> when the X axis is a rotation axis.

In the mirror device <NUM>, the width of each of the connection regions 40a and 40b in the X-axis direction is <NUM>% or less of the width of the mirror unit <NUM> in the X-axis direction. Accordingly, it is possible to secure a sufficient connection strength between the mirror unit <NUM> and the frame <NUM> and a sufficient distance between each of the torsion bars <NUM> and <NUM> and each of the connection regions 40a and 40b at the same time.

In the mirror device <NUM>, the coil <NUM> extends along each of the side surfaces 43b and 44b on the outside of each of the first portions <NUM> and <NUM> and extends along each of the side surfaces 45a and 46a on the inside of each of the second portions <NUM> and <NUM>. Accordingly, since the coil <NUM> is separated from each of the connection regions 40a and 40b and each of the torsion bars <NUM> and <NUM>, stress occurring in the coil <NUM> due to the twist of the pair of torsion bars <NUM> and <NUM> decreases. Thus, the occurrence of the metal fatigue in the coil <NUM> can be suppressed. As described above, stress is reduced in each of the connection regions 40a and 40b to a degree that the bending of the mirror unit <NUM> and the damage of the movable portion <NUM> are not caused, but there is concern that stress causing the metal fatigue of the coil <NUM> may remain. For that reason, it is effective from the viewpoint of safety to separate the coil <NUM> from each of the connection regions 40a and 40b by extending the coil <NUM> along each of the side surfaces 43b and 44b in each of the first portions <NUM> and <NUM>.

In the mirror device <NUM>, the slit 45c located between the torsion bar <NUM> and the mirror unit <NUM> is formed in the first portion <NUM> and the slit 46c located between the torsion bar <NUM> and the mirror unit <NUM> is formed in the first portion <NUM>. Accordingly, the influence of the twist of the pair of torsion bars <NUM> and <NUM> hardly reaches the coil <NUM>. Thus, the occurrence of the metal fatigue in the coil <NUM> can be suppressed. Furthermore, the influence of the twist of the pair of torsion bars <NUM> and <NUM> hardly reaches each of the connection regions 40a and 40b. Thus, it is possible to more reliably suppress both the bending of the mirror unit <NUM> and the damage of the movable portion <NUM>.

In the mirror device <NUM>, the coil <NUM> extends along the side surface 3b on the outside of the support portion <NUM>. Accordingly, since the coil <NUM> is separated from each of the torsion bars <NUM> and <NUM>, stress occurring in the coil <NUM> due to the twist of the pair of torsion bars <NUM> and <NUM> decreases. Thus, the occurrence of the metal fatigue in the coil <NUM> can be suppressed.

In the mirror device <NUM>, the curvature of the outer edge of the torsion bar <NUM> in a region connected to the outer edge of the second portion <NUM> is smaller than the curvature of the outer edge of the torsion bar <NUM> in a region connected to the inner edge of the support portion <NUM>. Similarly, the curvature of the outer edge of the torsion bar <NUM> in a region connected to the outer edge of the second portion <NUM> is smaller than the curvature of the outer edge of the torsion bar <NUM> in a region connected to the inner edge of the support portion <NUM>. When the curvature of the outer edge of each of the torsion bars <NUM> and <NUM> in a region connected to the frame <NUM> is decreased, stress occurring in the frame <NUM> due to the twist of the pair of torsion bars <NUM> and <NUM> can be decreased. Meanwhile, when the curvature of the outer edge of each of the torsion bars <NUM> and <NUM> in a region connected to the support portion <NUM> is increased, the length of each of the torsion bars <NUM> and <NUM> can be secured and stress due to the twist of the pair of torsion bars <NUM> and <NUM> can be decreased. Additionally, it is effective to decrease stress due to the twist of the pair of torsion bars <NUM> and <NUM> on the side of the movable portion <NUM> operated linearly in relation to the side of the support portion <NUM>.

In the mirror device <NUM>, the back surface of the support portion <NUM> is provided with the beam structure <NUM> extending in an annular shape along the frame-shaped support portion <NUM>. Accordingly, the deformation of the support portion <NUM> can be suppressed. Further, since the beam structure <NUM> is formed continuously, the occurrence of stress concentration can be suppressed as compared with a case in which the beam structure <NUM> is formed intermittently. Further, in the mirror device <NUM>, the width (the width in the X-axis direction) of the portion extending in the Y-axis direction in the beam structure <NUM> is smaller than the width (the width in the Y-axis direction) of the portion extending in the X-axis direction in the beam structure <NUM>. Accordingly, it is possible to decrease the inertia moment of the support portion <NUM> when the Y axis is a rotation axis. Further, in the mirror device <NUM>, the size of each of the punched portions 31a formed in the portion extending in the X-axis direction in the beam structure <NUM> becomes larger as it goes away from the Y axis. Accordingly, it is possible to decrease the inertia moment of the support portion <NUM> when the Y axis is a rotation axis. Further, in the mirror device <NUM>, the punched portion 31a is not formed in the intermediate portion crossing the Y axis in the beam structure <NUM>. Accordingly, it is possible to suppress the support portion <NUM> from swinging around the X axis as a center line by increasing the inertia moment of the support portion <NUM> when the X axis is a rotation axis. Furthermore, in the mirror device <NUM>, the center position of the portion extending in the Y-axis direction in the beam structure <NUM> is located on the outside of the center position of the portion extending in the Y-axis direction in the support portion <NUM>. Accordingly, since the portion extending in the Y-axis direction on the side of the torsion bar <NUM> in the beam structure <NUM> is separated from the torsion bar <NUM> and the portion extending in the Y-axis direction on the side of the torsion bar <NUM> in the beam structure <NUM> is separated from the torsion bar <NUM>, stress occurring in the beam structure <NUM> due to the twist of the pair of torsion bars <NUM> and <NUM> can be decreased.

In the mirror device <NUM>, the back surface of the mirror unit <NUM> is provided with the beam structure <NUM> extending from the intersection O in a V shape toward both edge portions of the connection region 40a in the X-axis direction and the beam structure <NUM> extending from the intersection O in a V shape toward both edge portions of the connection region 40b in the X-axis direction. Accordingly, stress occurring in each of the connection regions 40a and 40b due to the twist of the pair of torsion bars <NUM> and <NUM> can be decreased.

The present disclosure is not limited to the above-described embodiment. For example, the material and shape of each component are not limited to the materials and shapes described above and various materials and shapes can be employed. As an example, the frame <NUM> may have, for example, an outer shape of a polygonal shape other than a square shape when viewed from a direction perpendicular to the X axis and the Y axis if the frame is formed in a frame shape. Further, the mirror surface 41a may be formed in at least a part of the mirror unit <NUM>. Further, the shape of the mirror unit <NUM> when viewed from a direction perpendicular to the X axis and the Y axis may be a circular shape or the like. Further, the driving method of the mirror device <NUM> is not limited to the electromagnetic driving type and may be an electrostatic driving type, a piezoelectric driving type, a thermal driving type, or the like. Further, the base <NUM> and the pair of torsion bars <NUM> and <NUM> may not be provided in the mirror device <NUM> and the support portion <NUM> may function as the base.

Further, when the pair of torsion bars <NUM> and <NUM> is disposed on both sides of the movable portion <NUM> on the first axis, the pair of connection regions 40a and 40b may be located on both sides of the mirror unit <NUM> in a direction parallel to the second axis perpendicular to the first axis. As an example, when a pair of portions (portions forming opposite sides) of the polygonal frame-shaped frame <NUM> intersects the second axis, the pair of connection regions 40a and 40b may be disposed inside the pair of portions. In the above-described embodiment, the pair of connection regions 40a and 40b may be disposed inside the pair of first portions <NUM> and <NUM>. Alternatively, the pair of connection regions 40a and 40b may be disposed in a region of <NUM>° or more and <NUM>° or less in one direction from the first axis and a region of <NUM>° or more and <NUM>° or less in the other direction from the first axis with the intersection between the first axis and the second axis as a center point regardless of the shape of the frame <NUM>. Additionally, each of the connection regions 40a and 40b may be a plurality of physically divided regions.

Further, when the width of the first portion <NUM> in the Y-axis direction becomes smaller as it goes away from the connection region 40a, as illustrated in (a) of <FIG>, the side surface 43a on the inside of the first portion <NUM> may be a flat surface inclined so as to be closer to the side surface 43b on the outside of the first portion <NUM> as it goes away from the connection region 40a. Similarly, when the width of the first portion <NUM> in the Y-axis direction becomes smaller as it goes away from the connection region 40b, as illustrated in (a) of <FIG>, the side surface 44a on the inside of the first portion <NUM> may be a flat surface inclined so as to be closer to the side surface 44b on the outside of the first portion <NUM> as it goes away from the connection region 40b.

Further, when the width of the first portion <NUM> in the Y-axis direction becomes smaller as it goes away from the connection region 40a, as illustrated in (b) of <FIG>, the side surface 43a on the inside of the first portion <NUM> may be a bent surface bent stepwise so as to be closer to the side surface 43b on the outside of the first portion <NUM> as it goes away from the connection region 40a. Similarly, when the width of the first portion <NUM> in the Y-axis direction becomes smaller as it goes away from the connection region 40b, as illustrated in (b) of <FIG>, the side surface 44a on the inside of the first portion <NUM> may be a bent surface bent stepwise so as to be closer to the side surface 44b on the outside of the first portion <NUM> as it goes away from the connection region 40b.

Further, in the movable portion <NUM> of the third modified example, as illustrated in <FIG>, the mirror unit <NUM> is connected to the frame <NUM> in each of the pair of connection regions (first connection regions) 40a and 40b located on both sides of the mirror unit <NUM> in the Y-axis direction and each of the pair of connection regions (second connection regions) 40c and 40d located on both sides of the mirror unit <NUM> in the X-axis direction. In the region between the mirror unit <NUM> and the frame <NUM>, a region other than the pair of connection regions 40a and 40b and the pair of connection regions 40c and 40d is a space. That is, the mirror unit <NUM> and the frame <NUM> are connected to each other only in the pair of connection regions 40a and 40b and the pair of connection regions 40c and 40d.

The side surface 41b of the mirror unit <NUM> and the side surface 43a on the inside of the first portion <NUM> are connected to each other so that the curvature in the connection region 40a is continuous. The side surface 41b of the mirror unit <NUM> and the side surface 44a on the inside of the first portion <NUM> are connected to each other so that the curvature in the connection region 40b is continuous. That is, the outer edge of the mirror unit <NUM> and the inner edge of the frame <NUM> are connected to each other so that the curvature in each of the connection regions 40a and 40b is continuous when viewed from a direction perpendicular to the X axis and the Y axis.

The side surface 41b of the mirror unit <NUM> and the side surface 45a on the inside of the second portion <NUM> are connected to each other so that the curvature in the connection region 40d is continuous. The side surface 41b of the mirror unit <NUM> and the side surface 46a on the inside of the second portion <NUM> are connected to each other so that the curvature in the connection region 40c is continuous. That is, the outer edge of the mirror unit <NUM> and the inner edge of the frame <NUM> are connected to each other so that the curvature in each of the connection regions 40c and 40d is continuous when viewed from a direction perpendicular to the X axis and the Y axis.

The width of the first portion <NUM> in the Y-axis direction becomes smaller as it goes away from the connection region 40a. Here, the side surface 43b on the outside of the first portion <NUM> becomes a flat surface parallel to the X axis and the side surface 43a on the inside of the first portion <NUM> becomes a surface closer to the side surface 43b as it goes away from the connection region 40a. The width of the first portion <NUM> in the Y-axis direction becomes smaller as it goes away from the connection region 40b. Here, the side surface 44b on the outside of the first portion <NUM> becomes a flat surface parallel to the X axis and the side surface 44a on the inside of the first portion <NUM> becomes a surface closer to the side surface 44b as it goes away from the connection region 40b.

In addition, the side surface 43a on the inside of the first portion <NUM> may be a flat surface inclined so as to be closer to the side surface 43b on the outside of the first portion <NUM> as it goes away from the connection region 40a. Similarly, the side surface 44a on the inside of the first portion <NUM> may be a flat surface inclined so as to be closer to the side surface 44b on the outside of the first portion <NUM> as it goes away from the connection region 40b. Further, the side surface 43a on the inside of the first portion <NUM> may be a bent surface bent stepwise so as to be closer to the side surface 43b on the outside of the first portion <NUM> as it goes away from the connection region 40a. Similarly, the side surface 44a on the inside of the first portion <NUM> may be a bent surface bent stepwise so as to be closer to the side surface 44b on the outside of the first portion <NUM> as it goes away from the connection region 40b.

The width of the second portion <NUM> in the X-axis direction becomes smaller as it goes away from the connection region 40d. Here, the side surface 45b on the outside of the second portion <NUM> becomes a flat surface parallel to the Y axis and the side surface 45a on the inside of the second portion <NUM> becomes a surface closer to the side surface 45b as it goes away from the connection region 40d. The width of the second portion <NUM> in the X-axis direction becomes smaller as it goes away from the connection region 40c. Here, the side surface 46b on the outside of the second portion <NUM> becomes a flat surface parallel to the Y axis and the side surface 46a on the inside of the second portion <NUM> becomes a surface closer to the side surface 46b as it goes away from the connection region 40c.

In addition, the side surface 45a on the inside of the second portion <NUM> may be a flat surface inclined so as to be closer to the side surface 45b on the outside of the second portion <NUM> as it goes away from the connection region 40d. Similarly, the side surface 46a on the inside of the second portion <NUM> may be a flat surface inclined so as to be closer to the side surface 46b on the outside of the second portion <NUM> as it goes away from the connection region 40c. Further, the side surface 45a on the inside of the second portion <NUM> may be a bent surface bent stepwise so as to be closer to the side surface 45b on the outside of the second portion <NUM> as it goes away from the connection region 40d. Similarly, the side surface 46a on the inside of the second portion <NUM> may be a bent surface bent stepwise so as to be closer to the side surface 46b on the outside of the second portion <NUM> as it goes away from the connection region 40c.

In the mirror device <NUM> including the movable portion <NUM> of the third modified example, the pair of torsion bars <NUM> and <NUM> connected to the frame-shaped frame <NUM> is disposed on the X axis and the pair of connection regions 40a and 40b in which the mirror unit <NUM> and the frame-shaped frame <NUM> are connected to each other is located on both sides of the mirror unit <NUM> in the Y-axis direction. Furthermore, the pair of connection regions 40c and 40d in which the mirror unit <NUM> and the frame-shaped frame <NUM> are connected to each other is located on both sides of the mirror unit <NUM> in the X-axis direction. Accordingly, even when the movable portion <NUM> is swung at a high speed while using the X axis as a center line, stress occurring in each of the connection regions 40a, 40b, 40c, and 40d due to the twist of the pair of torsion bars <NUM> and <NUM> becomes smaller than, for example, a case in which only the pair of connection regions 40a and 40b is located on the X axis or a case in which the mirror unit <NUM> and the frame-shaped frame <NUM> are connected to each other only in one connection region 40a (or 40b). Further, in the mirror device <NUM> including the movable portion <NUM> of the third modified example, the outer edge of the mirror unit <NUM> and the inner edge of the frame <NUM> are connected to each other so that the curvature in each of the connection regions 40a and 40b is continuous when viewed from a direction perpendicular to the X axis and the Y axis. Accordingly, stress concentration hardly occurs in each of the connection regions 40a and 40b. As described above, according to the mirror device <NUM> including the movable portion <NUM> of the third modified example, both the bending of the mirror unit <NUM> and the damage of the movable portion <NUM> can be suppressed.

In the mirror device <NUM> including the movable portion <NUM> of the third modified example, the outer edge of the mirror unit <NUM> and the inner edge of the frame <NUM> are connected to each other so that the curvature in each of the connection regions 40c and 40d is continuous when viewed from a direction perpendicular to the X axis and the Y axis. Accordingly, stress concentration hardly occurs in each of the connection regions 40c and 40d.

In the mirror device <NUM> including the movable portion <NUM> of the third modified example, the pair of connection regions 40c and 40d is located on both sides of the mirror unit <NUM> on the X axis. Accordingly, the inertia moment of the movable portion around the X axis can be decreased.

The pair of torsion bars <NUM> and <NUM> is disposed on both sides of the movable portion <NUM> on the first axis, and the pair of connection regions 40c and 40d is located on both sides of the mirror unit <NUM> in a direction parallel to the first axis. As an example, when a pair of portions (portions forming opposite sides) of the polygonal frame-shaped frame <NUM> intersects the first axis, the pair of connection regions 40c and 40d may be disposed inside the pair of portions. In the movable portion <NUM> of the third modified example, the pair of connection regions 40c and 40d may be disposed inside the pair of second portions <NUM> and <NUM>. Alternatively, the pair of connection regions 40c and 40d may be disposed in a region of <NUM>° or more and <NUM>° or less in one direction from the second axis and a region of <NUM>° or more and <NUM>° or less in the other direction from the second axis with the intersection between the first axis and the second axis as a center point regardless of the shape of the frame <NUM>. Additionally, each of the connection regions 40c and 40d may be a plurality of physically divided regions.

In the mirror device <NUM> including the movable portion <NUM> of the third modified example, the width of each of the first portions <NUM> and <NUM> in the Y-axis direction becomes smaller as it goes away from each of the connection regions 40a and 40b and the width of each of the second portions <NUM> and <NUM> in the X-axis direction becomes smaller as it goes away from each of the connection regions 40c and 40d. Accordingly, stress due to the twist of the pair of torsion bars <NUM> and <NUM> is dispersed in the portion of which the width is smaller than that of each of the first portions <NUM> and <NUM> and each of the second portions <NUM> and <NUM> so that stress occurring in each of the connection regions 40a, 40b, 40c, and 40d can be further decreased. Furthermore, it is possible to decrease the inertia moment of the movable portion <NUM> when the X axis is a rotation axis as the width of each of the first portions <NUM> and <NUM> and each of the second portions <NUM> and <NUM> decreases while securing the connection strength in each of the connection regions 40a, 40b, 40c, and 40d. Here, the width of each of the second portions <NUM> and <NUM> in the X-axis direction may not decrease as it goes away from each of the connection regions 40c and 40d.

In the mirror device <NUM> including the movable portion <NUM> of the third modified example, the slit 45c located between the torsion bar <NUM> and the mirror unit <NUM> is formed in the first portion <NUM> and the slit 46c located between the torsion bar <NUM> and the mirror unit <NUM> is formed in the first portion <NUM>. Furthermore, the curvature of the outer edge of the torsion bar <NUM> in a region connected to the outer edge of the second portion <NUM> is smaller than the curvature of the outer edge of the torsion bar <NUM> in a region connected to the inner edge of the support portion <NUM>. Similarly, the curvature of the outer edge of the torsion bar <NUM> in a region connected to the outer edge of the second portion <NUM> is smaller than the curvature of the outer edge of the torsion bar <NUM> in a region connected to the inner edge of the support portion <NUM>. Accordingly, in the mirror device <NUM> including the movable portion <NUM> of the third modified example, the influence of the twist of the pair of torsion bars <NUM> and <NUM> hardly reaches the pair of connection regions 40c and 40d while realizing a stable support of the mirror unit <NUM> by four connection regions 40a, 40b, 40c, and 40d.

Each of the configurations of the above-described embodiments is also applied to the mirror device <NUM> including the movable portion <NUM> of the third modified example. For example, the inner edge of each of the first portions <NUM> and <NUM> and the inner edge of each of the second portions <NUM> and <NUM> are connected to each other so that the curvature in each connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. Further, the outer edge of each the first portions <NUM> and <NUM> and the outer edge of each of the second portions <NUM> and <NUM> are connected to each other so that the curvature in each connection region is continuous when viewed from a direction perpendicular to the X axis and the Y axis. Further, the length of each of the first portions <NUM> and <NUM> in the X-axis direction is longer than the length of each of the second portions <NUM> and <NUM> in the Y-axis direction. Further, each of the distance between the connection region 40a and the second portion <NUM>, the distance between the connection region 40a and the second portion <NUM>, the distance between the connection region 40b and the second portion <NUM>, and the distance between the connection region 40b and the second portion <NUM> is longer than each of the distance between the X axis and the first portion <NUM> and the distance between the X axis and the first portion <NUM>. Further, the shape of the mirror unit <NUM> when viewed from a direction perpendicular to the X axis and the Y axis is an ellipse having a major axis along the X axis. Further, the width of each of the connection regions 40a and 40b in the X-axis direction is <NUM>% or less of the width of the mirror unit <NUM> in the X-axis direction. Further, the coil <NUM> extends along each of the side surfaces 43b and 44b on the outside of each of the first portions <NUM> and <NUM> and extends along each of the side surfaces 45a and 46a on the inside of each of the second portions <NUM> and <NUM>. Further, the coil <NUM> extends along the side surface 3b on the outside of the support portion <NUM>. Further, the back surface of the support portion <NUM> is provided with the beam structure <NUM> extending in an annular shape along the frame-shaped support portion <NUM>. Further, the back surface of the mirror unit <NUM> is provided with the beam structure <NUM> extending from the intersection O in a V shape toward both edge portions of the connection region 40a in the X-axis direction and the beam structure <NUM> extending from the intersection O in a V shape toward both edge portions of the connection region 40b in the X-axis direction.

Also in the mirror device <NUM> including the movable portion <NUM> of the third modified example, the material and shape of each component are not limited to the materials and shapes described above and various materials and shapes can be adopted. As an example, the frame <NUM> may have, for example, an outer shape such as a polygonal shape other than a square shape when viewed from a direction perpendicular to the X axis and the Y axis if the frame is formed in a frame shape. Further, the mirror surface 41a may be formed in at least a part of the mirror unit <NUM>. Further, the shape of the mirror unit <NUM> when viewed from a direction perpendicular to the X axis and the Y axis may be a circular shape or the like.

In the embodiments and modified examples described above, the coil <NUM> for swinging the movable portion <NUM> is provided in the movable portion <NUM> and the coil <NUM> for swinging the support portion <NUM> is provided in the support portion <NUM>. However, each of the coil for swinging the movable portion <NUM> and the coil for swinging the support portion <NUM> may be provided in the support portion <NUM> or a single coil for swinging the movable portion <NUM> and the support portion <NUM> may be provided in the support portion <NUM>.

Each configuration in one embodiment or modified example described above can be arbitrarily applied to each configuration in another embodiment or modified example, wherein the scope of the invention is defined by the appended claims.

Claim 1:
A mirror device (<NUM>) comprising:
a support portion (<NUM>);
a movable portion (<NUM>); and
a pair of torsion bars (<NUM>, <NUM>) disposed on both sides of the movable portion (<NUM>) on a first axis (X) and connecting the movable portion (<NUM>) to the support portion (<NUM>) so that the movable portion (<NUM>) is swingable around the first axis (X) as a center line,
wherein the movable portion (<NUM>) includes a frame-shaped frame (<NUM>) connected to the pair of torsion bars (<NUM>, <NUM>) and a mirror unit (<NUM>) disposed inside the frame (<NUM>),
wherein the mirror unit (<NUM>) is connected to the frame (<NUM>) in each of a pair of first connection regions (40a, 40b) located on both sides of the mirror unit (<NUM>) in a direction parallel to a second axis (Y) perpendicular to the first axis (X),
wherein a region other than the pair of first connection regions (40a, 40b) in a region between the mirror unit (<NUM>) and the frame (<NUM>) is a space,
characterized in that an outer edge of the mirror unit (<NUM>) and an inner edge of the frame (<NUM>) are connected to each other so that a curvature in each of the pair of first connection regions (40a, 40b) is continuous when viewed from a direction perpendicular to the first axis (X) and the second axis (Y), and
side surfaces (7a) on both sides of each of the pair of torsion bars (<NUM>, <NUM>) and a side surface on an outside of the frame (<NUM>) are connected to each other so that a curvature in each connection region is continuous when viewed from a direction perpendicular to the first axis (X) and the second axis (Y).