Mirror unit

In a mirror unit, a first wall portion is higher than a second wall portion. A window member is disposed on a top surface of the first wall portion and a top surface of the second wall portion and is inclined with respect to a mirror surface. When any one of first to fourth wall portions is set as a first reference wall portion, in a cross-section perpendicular to the first reference wall portion, a first line passing through a first end at a side of the first reference wall portion in the mirror surface and a first corner portion formed at the side of the first reference wall portion by an outer surface and a first side surface in the window member intersects the first wall portion. A wiring portion includes a portion extending inside a base and leads outside a frame member.

TECHNICAL FIELD

An aspect of the present disclosure relates to a mirror unit.

BACKGROUND

Japanese Unexamined Patent Publication No. 2017-215352 discloses a mirror unit including an optical scanning device having a mirror surface provided on a movable portion, a frame member disposed so as to surround the optical scanning device, and a flat window member covering an opening of the frame member. Light is incident to the mirror surface through the window member from the outside, is reflected by the mirror surface, and is emitted to the outside through the window member.

SUMMARY

In the mirror unit described in Japanese Unexamined Patent Publication No. 2017-215352, a height of one of a pair of wall portions constituting the frame member and facing each other is formed to be higher than the other and the window member disposed on the frame member is inclined with respect to the mirror surface. When the window member is inclined with respect to the mirror surface, the traveling direction of the light reflected by the window member can be different from the traveling direction of the light reflected by the mirror surface and the light reflected by the window member can be prevented from to be noise light.

Meanwhile, in the configuration in which optical scanning is performed by swinging the movable portion provided with the mirror surface as in the mirror unit, the light incident angle to the window member increases in accordance with the angle of the mirror surface and the refraction angle of the light emitted from the window member increases. Particularly, in the above-described configuration in which the window member is inclined, the light incident angle to the window member further increases. For that reason, it is necessary to consider the influence of refraction at the window member in order to realize high-accuracy optical scanning. Here, it is conceivable to restrain the influence of refraction at the window member by thinning the window member to reduce the refraction amount at the window member. However, when the window member is formed to be thin, the strength of the window member decreases and the window member is likely to be broken. For that reason, it is required to prevent the damage of the window member. Further, it is also required to improve reliability in the above-described mirror unit.

An object of an aspect of the present disclosure is to provide a mirror unit capable of preventing damage of a window member while reducing noise light and improving reliability.

A mirror unit according to an aspect of the present disclosure includes: a base; an optical scanning device that includes a movable portion and a mirror surface provided on the movable portion and is disposed on the base; a frame member disposed on the base so as to surround the optical scanning device when viewed from a first direction; a window member formed in a plate shape and disposed on the frame member so as to cover an opening of the frame member; and a wiring portion electrically connected to the optical scanning device, in which the frame member includes a first wall portion and a second wall portion which face each other in a second direction perpendicular to the first direction and a third wall portion and a fourth wall portion which face each other in a third direction perpendicular to both the first direction and the second direction, in which a height of the first wall portion is higher than a height of the second wall portion, in which the window member is disposed on a top surface of the first wall portion and a top surface of the second wall portion and is inclined with respect to the mirror surface, in which when any one of the first wall portion, the second wall portion, the third wall portion, and the fourth wall portion is set as a first reference wall portion, in a cross-section passing through the mirror surface and perpendicular to the first reference wall portion, a first line passing through a first end at a side of the first reference wall portion in the mirror surface and a first corner portion formed at the side of the first reference wall portion by an outer surface opposite to the frame member and a first side surface in the window member intersects the first reference wall portion, and in which the wiring portion includes a portion extending inside the base and leads outside the frame member.

In the mirror unit, the height of the first wall portion is higher than the height of the second wall portion and the window member is disposed on the top surface of the first wall portion and the top surface of the second wall portion and is inclined with respect to the mirror surface. Accordingly, the traveling direction of the light reflected by the window member can be different from the traveling direction of the light reflected by the mirror surface and the light reflected by the window member can be prevented from to be noise light. Further, when any one of the first wall portion, the second wall portion, the third wall portion, and the fourth wall portion is set as the first reference wall portion, in the cross-section passing through the mirror surface and perpendicular to the first reference wall portion, the first line passing through the first end at the side of the first reference wall portion in the mirror surface and the first corner portion formed at the side of the first reference wall portion by the outer surface and the first side surface in the window member intersects the first reference wall portion. Since the first line is formed so as to intersect the first wall portion, the first reference wall portion is formed to be relatively thicker with respect to the window member. Accordingly, it is possible to support the window member by the thick first reference wall portion and to prevent the damage of the window member. Meanwhile, when the first reference wall portion is formed to be thick, it is conceivable to widen the thickness of the first reference wall portion toward the optical scanning device from the viewpoint of miniaturization. However, in that case, the area of the portion located at the inside of the frame member on the base is narrowed. When a wiring portion for electrical connection to the optical scanning device is formed in such a narrow portion, there is concern that defects such as short circuit or the like may occur in the wiring portion. In contrast, in the mirror unit, the wiring portion includes a portion extending inside the base and leads outside the frame member. Since the wiring portion is formed inside the base as such, it is possible to prevent defects such as short circuit or the like in the wiring portion. Further, for example, compared to a case in which the wiring portion is formed so as to extend along the surface of the base between the base and the frame member, the deterioration of the wiring portion can be prevented and the influence of the wiring portion on the bonding portion between the base and the frame member can be prevented. Thus, according to the mirror unit, it is possible to prevent the damage of the window member while reducing noise light and to improve the reliability.

The window member may be bonded to the frame member and a thickness of the window member may be smaller than a width of a region in which the window member and the frame member are bonded to each other. In this case, the window member can be formed to be thin and hence the influence of refraction at the window member can be restrained.

When one facing the first reference wall portion among the first wall portion, the second wall portion, the third wall portion, and the fourth wall portion is set as a second reference wall portion, in the cross-section, a second line passing through a second end at a side of the second reference wall portion in the mirror surface and a second corner portion formed at the side of the second reference wall portion by the outer surface and a second side surface in the window member may intersect the second reference wall portion. In this case, since the second reference wall portion is formed to be relatively thicker with respect to the window member, it is possible to support the window member by the thick second reference wall portion and to further reliably prevent the damage of the window member.

The wiring portion may extend inside the base so as to overlap the first reference wall portion when viewed from the first direction. When the wiring portion is to be pulled out toward the thick first reference wall portion, the above-described deterioration of the wiring portion or the like tends to occur. However, in the mirror unit, since the wiring portion is formed inside the base, it is possible to reliably prevent deterioration of the wiring portion or the like.

The wiring portion may include an electrode pad provided on the base in a region located at an inside of the frame member when viewed from the first direction, when one facing the first reference wall portion among the first wall portion, the second wall portion, the third wall portion, and the fourth wall portion is set as a second reference wall portion, a distance between the optical scanning device and the first reference wall portion may be longer than a distance between the optical scanning device and the second reference wall portion, and the electrode pad may be disposed between the optical scanning device and the first reference wall portion on the base. In this case, it is possible to ensure a space for disposing the electrode pad.

The first reference wall portion may be the first wall portion and the second reference wall portion may be the second wall portion. In this case, since the first wall portion is separated from the optical scanning device compared to the second wall portion, it is possible to prevent the light reflected by the mirror surface from being interrupted by the first wall portion higher than the second wall portion.

The wiring portion may be electrically connected to the optical scanning device in a first region located at an inside of the frame member when viewed from the first direction, extend inside the base in a second region overlapping the frame member when viewed from the first direction, and leads out to a third region located at an outside of the frame member when viewed from the first direction. In this case, it is possible to further reliably prevent deterioration of the wiring portion or the like.

According to an aspect of the present disclosure, it is possible to provide a mirror unit capable of preventing damage of a window member while reducing noise light and improving reliability.

DETAILED DESCRIPTION

Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. In the description below, the same or corresponding components will be denoted by the same reference numerals and redundant description will be omitted.

[Overall Configuration of Mirror Unit]

As illustrated inFIG. 1, a mirror unit100includes an optical scanning device1and a package40accommodating the optical scanning device1. The package40includes a base42, a frame member43, and a window member44.

The base42is formed in a rectangular plate shape from, for example, a non-magnetic material such as aluminum nitride or aluminum oxide. The base42includes a main surface42aand a rear surface42bon the side opposite to the main surface42a. The main surface42ais a surface constituting a part of the inner surface of the package40. The main surface42ais provided with a depression42c. A bottom surface of the depression42cis provided with a depression42d. The optical scanning device1is disposed on the base42, more specifically, a bottom surface of the depression42c. A magnetic field generating unit (not illustrated) which generates a magnetic field acting on a first drive coil11and a second drive coil12of the optical scanning device1to be described later is disposed on the side of the rear surface42bof the base42. The magnetic field generating unit includes, for example, permanent magnets in a Halbach array.

The frame member43is disposed on the main surface42aso as to surround the optical scanning device1(to surround a mirror surface7ato be described later) when viewed from the Z-axis direction (the first direction) perpendicular to the main surface42aof the base42. The frame member43is formed in a rectangular frame shape from, for example, a non-magnetic material such as aluminum nitride or aluminum oxide.

The window member44is configured by, for example, forming an anti-reflection film on both surfaces of a rectangular plate base material formed of a light-transmitting material such as glass. The window member44is disposed on the frame member43so as to cover one opening43aof the frame member43and faces the base42and the optical scanning device1in the Z-axis direction. The window member44is bonded to the frame member43by, for example, a bonding material45such as low-melting glass so as to hermetically seal the opening43a.

The base42is bonded to the frame member43by, for example, a bonding material46such as low-melting glass so as to hermetically seal the other opening43bof the frame member43. Accordingly, the inside of the package40is hermetically sealed. The base42and the frame member43may be integrally formed so as to configure a single member.

The bonding with the bonding materials45and46is not limited to the bonding with the low-melting glass and may be, for example, bonding with resin adhesive, low-temperature solder (Sn/Pb or Sn/Cu-based), low-temperature brazing material (Au/Sn alloy, Au/Ge alloy, or the like), high-temperature brazing material (Ag-based or the like), projection welding, seam seal welding, laser welding, electron beam welding, or the like.

[Configuration of Optical Scanning Device]

As illustrated inFIG. 2, the optical scanning device1includes a support portion2and a movable portion10which is swingable with respect to the support portion2. The movable portion10includes a first movable portion3, a second movable portion4, a pair of first connection portions5, a pair of second connection portions6, and a mirror7. The support portion2, the first movable portion3, the second movable portion4, the pair of first connection portions5, and the pair of second connection portions6are integrally formed by, for example, a Silicon on Insulator (SOI) substrate. That is, the optical scanning device1is configured as a Micro Electro Mechanical Systems (MEMS) device.

The first movable portion3is formed in, for example, a rectangular plate shape. The second movable portion4is formed in, for example, a rectangular ring shape so as to surround the first movable portion3with a gap when viewed from an optical axis direction A. The support portion2is formed in, for example, a rectangular ring shape so as to surround the second movable portion4with a gap when viewed from the optical axis direction A. That is, the support portion2is formed in a frame shape so as to surround the first movable portion3and the second movable portion4when viewed from the optical axis direction A.

The first movable portion3is connected to the second movable portion4via the pair of first connection portions5so as to be swingable around a first axis X1. That is, the first movable portion3is supported by the support portion2so as to be swingable around the first axis X1. The first movable portion3includes a first portion31and a second portion32. The first portion31is formed in, for example, a circular shape when viewed from the optical axis direction A. The second portion32is formed in, for example, a rectangular ring shape when viewed from the optical axis direction A. The first portion31is surrounded by the second portion32when viewed from the optical axis direction A and is connected to the second portion32via a plurality of (in this example, two) connection portions33. That is, gaps are formed between the first portion31and the second portion32except for the plurality of connection portions33.

The connection portion33is located, for example, at the center of two sides of the rectangular inner edge of the second portion32intersecting a second axis X2. That is, in this example, the connection portion33is located on the second axis X2. The first portion31may be connected to the second portion32in a direction along at least the second axis X2.

The second movable portion4is connected to the support portion2via the pair of second connection portions6so as to be swingable around the second axis X2. That is, the second movable portion4is supported by the support portion2so as to be swingable around the second axis X2. The first axis X1and the second axis X2are perpendicular to the optical axis direction A and intersect each other (orthogonal to each other in this example). The first portion31may be formed in a rectangular shape or polygonal shape when viewed from the optical axis direction A. The first portion31may be formed in a circular shape (for example, an oval shape) when viewed from the optical axis direction A. The second portion32may be formed in a ring shape or a polygonal ring shape of a pentagon or more when viewed from the optical axis direction A.

The pair of first connection portions5are disposed on the first axis X1so as to sandwich the first movable portion3in a gap between the second movable portion4and the second portion32of the first movable portion3. Each first connection portion5functions as a torsion bar. The pair of second connection portions6is disposed on the second axis X2so as to sandwich the second movable portion4in a gap between the second movable portion4and the support portion2. Each second connection portion6functions as a torsion bar.

The mirror7is provided on the first portion31of the first movable portion3. The mirror7is formed on the surface at the side opposite to the base42(at the side of the window member44) in the first portion31so as to include an intersection point between the first axis X1and the second axis X2. For example, the mirror7is formed in a circular, oval, or rectangular film shape from a metal material such as aluminum, an aluminum-based alloy, gold, or silver. A surface at the side opposite to the first movable portion3in the mirror7constitutes the mirror surface7aextending in a direction perpendicular to the optical axis direction A. The center (geometric center, centroid) of the mirror surface7amatches the intersection between the first axis X1and the second axis X2when viewed from the optical axis direction A. In this way, since the mirror7is provided on the first portion31connected to the second portion32through the plurality of connection portions33, deformation such as bending of the mirror7can be prevented even when the first movable portion3swings around the first axis X1at the resonant frequency level.

The distance from the outer edge of the mirror surface7ato the outer edge of the first portion31is smaller than the width of the connection portion33. The width of the connection portion33is the length in a direction (in this example, a direction along the first axis X1) perpendicular to the extension direction of the connection portion33(in this example, a direction along the second axis X2). The first movable portion3may not include the second portion32and the connection portion33. The distance from the outer edge of the mirror surface7ato the outer edge of the first portion31may be smaller than the width of the second connection portion6. The width of the second connection portion6is the length in a direction (in this example, a direction along the first axis X1) perpendicular to the extension direction of the second connection portion6(in this example, a direction along the second axis X2).

Further, the optical scanning device1includes a first drive coil11, a second drive coil12, wirings15aand15b, wirings16aand16b, electrode pads21aand21b, and electrode pads22aand22b. InFIG. 2, for convenience of description, the first drive coil11and the second drive coil12are indicated by a one dotted chain line and the wirings15aand15band the wirings16aand16bare indicated by a solid line.

The first drive coil11is provided in the second portion32of the first movable portion3. The first drive coil11is wound a plurality of times in a spiral shape (a swirl shape) in a region outside the mirror7(that is, the second portion32) when viewed from the optical axis direction A. A magnetic field generated by the magnetic field generating unit acts on the first drive coil11.

The first drive coil11is disposed in a groove formed on the surface of the first movable portion3. That is, the first drive coil11is buried in the first movable portion3. One end of the first drive coil11is connected to the electrode pad21athrough the wiring15a. The wiring15aextends from the first movable portion3to the support portion2through one first connection portion5, the second movable portion4, and one second connection portion6. For example, the wiring15aand the electrode pad21aare integrally formed of a metal material such as tungsten, aluminum, gold, silver, copper, or an aluminum-based alloy.

The other end of the first drive coil11is connected to the electrode pad21bthrough the wiring15b. The wiring15bextends from the first movable portion3to the support portion2through the other first connection portion5, the second movable portion4, and the other second connection portion6. For example, the wiring15band the electrode pad21bare integrally formed of a metal material such as tungsten, aluminum, gold, silver, copper, or an aluminum-based alloy.

The second drive coil12is provided in the second movable portion4. The second drive coil12is wound a plurality of times in a spiral shape (a swirl shape) in the second movable portion4. A magnetic field generated by the magnetic field generating unit acts on the second drive coil12. The second drive coil12is disposed in a groove formed on the surface of the second movable portion4. That is, the second drive coil12is buried in the second movable portion4.

One end of the second drive coil12is connected to the electrode pad22athrough the wiring16a. The wiring16aextends from the second movable portion4to the support portion2through one second connection portion6. For example, the wiring16aand the electrode pad22aare integrally formed of a metal material such as tungsten, aluminum, gold, silver, copper, or an aluminum-based alloy.

The other end of the second drive coil12is connected to the electrode pad22bthrough the wiring16b. The wiring16bextends from the second movable portion4to the support portion2through the other second connection portion6. For example, the wiring16band the electrode pad22bare integrally formed of a metal material such as tungsten, aluminum, gold, silver, copper, or an aluminum-based alloy.

The number and arrangement of the electrode pads21a,21b,22a, and22bare not limited to the example illustrated inFIG. 4. As in the example ofFIG. 4, the electrode pad21amay be disposed at one side of the second axis X2with respect to the movable portion10and the electrode pad21bmay be disposed at the other side of the second axis X2with respect to the movable portion10. Alternatively, both the electrode pads21aand21bmay be disposed at one side or the other side of the second axis X2with respect to the movable portion10. In the latter case, the wirings15aand15bmay extend on the same second connection portion6. These points are the same in the electrode pads22aand22band the wirings16aand16b.

Hereinafter, first to fifth examples will be described as an operation example of the movable portion10of the optical scanning device1. In the first example, a high-frequency drive current is applied to the first drive coil11. At this time, since a magnetic field generated by the magnetic field generating unit acts on the first drive coil11, a Lorentz force is generated in the first drive coil11. Accordingly, the first movable portion3is swung around the first axis X1, for example, at the resonant frequency level.

Further, a drive current of a certain magnitude is applied to the second drive coil12. At this time, since a magnetic field generated by the magnetic field generating unit acts on the second drive coil12, a Lorentz force is generated in the second drive coil12. Accordingly, the second movable portion4is rotated around the second axis X2, for example, in response to the magnitude of the drive current and is stopped at that state. Accordingly, according to the optical scanning device1, light emitted from a predetermined light source can be scanned while being reflected by the mirror surface7a. Light is incident to the mirror surface7athrough the window member44from the outside, is reflected by the mirror surface7a, and is emitted to the outside through the window member44. In the first example, the first movable portion3is swung at the resonant frequency and the second movable portion4is used statically.

In the second example, similarly to the operation of the first movable portion3of the first example, the first movable portion3is swung in response to the resonant frequency when a high-frequency drive current is applied to the first drive coil11and the second movable portion4is swung in response to the resonant frequency when a high-frequency drive current is applied to the second drive coil12. In this way, in the second example, both the first movable portion3and the second movable portion4are swung at the resonant frequency.

In the third example, similarly to the operation of the second movable portion4of the first example, the first movable portion3is rotated and stopped around the first axis X1in response to the magnitude of the drive current when a drive current of a certain magnitude is applied to the first drive coil11and the second movable portion4is rotated and stopped around the second axis X2in response to the magnitude of the drive current when a drive current of a certain magnitude is applied to the second drive coil12. In this way, in the third example, both the first movable portion3and the second movable portion4are used statically.

In the fourth example and the fifth example, only the first movable portion3is driven. In the fourth example, since a high-frequency drive current is applied to the first drive coil11, the first movable portion3is swung in response to the resonant frequency. In the fifth example, since a drive current of a certain magnitude is applied to the first drive coil11, the first movable portion3is rotated and stopped around the first axis X1in response to the magnitude of the drive current. The fourth example and the fifth example can be used, for example, in a case in which the second movable portion4is not provided or the like.

As described above, the optical scanning device1is disposed on the base42. The support portion2is fixed to the bottom surface of the depression42cand the first movable portion3and the second movable portion4face the bottom surface of the depression42d. Since the depression42dis provided, the first movable portion3and the second movable portion4can swing without interfering with the base42.

As illustrated inFIGS. 1 and 3, the frame member43includes a first wall portion51, a second wall portion52, a third wall portion53, and a fourth wall portion54. Each of the wall portions51to54is formed in a plate shape and has the same thickness. The first wall portion51and the second wall portion52extend in parallel to each other and face each other in the X-axis direction (the second direction) perpendicular to the Z-axis direction. The third wall portion53and the fourth wall portion54extend in parallel to each other and face each other in the Y-axis direction (the third direction) perpendicular to both the Z-axis direction and the X-axis direction. The third wall portion53is connected to one end of the first wall portion51and one end of the second wall portion52and the fourth wall portion54is connected to the other end of the first wall portion51and the other end of the second wall portion52. The third wall portion53and the fourth wall portion54have, for example, the same shape.

A top surface51aat the side opposite to the base42in the first wall portion51is inclined with respect to the main surface42aso as to move away from the main surface42aof the base42as it goes away from the second wall portion52. A top surface52aat the side opposite to the base42in the second wall portion52is inclined with respect to the main surface42aso as to move away from the main surface42aof the base42as it goes toward the first wall portion51. A height H1of the first wall portion51is higher than a height H2of the second wall portion52. The height H1of the first wall portion51is a maximum value of the distance from the main surface42ato the top surface51aand the height H2of the second wall portion52is a maximum value from the main surface42ato the top surface52a.

A top surface53aat the side opposite to the base42in the third wall portion53is inclined with respect to the main surface42aso as to move away from the main surface42aof the base42as it goes toward the first wall portion51when viewed from the Y-axis direction. A top surface54aat the side opposite to the base42in the fourth wall portion54is inclined with respect to the main surface42aso as to move away from the main surface42aof the base42as it goes toward the first wall portion51when viewed from the Y-axis direction.

The top surfaces51ato54aare flush with one other and located on the same plane. The window member44is disposed on the top surfaces51ato54aand is inclined with respect to the main surface42a(the mirror surface7a) so as to move away from the main surface42aas it goes from the second wall portion52toward the first wall portion51. In other words, each of the top surfaces51ato54ais inclined corresponding to an angle of the inclination of the window member44.

The first wall portion51may be formed by a plurality of portions. These portions may be forming separately with a gap provided therebetween. In the embodiment, the entire top surface51ais formed flat, but the top surface51amay be divided into a plurality of regions by forming a notch, a depression, a convex portion, or the like on the top surface51a. The entire top surface51adoes not need to be inclined at an angle corresponding to the inclination of the window member44. For example, a line connecting two points in the top surface51amay be inclined at an angle corresponding to the inclination of the window member44. These matters are the same for the second wall portion52to the fourth wall portion54. The window member44may not be bonded to the frame member43in the entire top surfaces51ato54aand may be boded to the frame member43in at least a part of the top surfaces51ato54a.

The window member44includes an outer surface44a, an inner surface44b, a first side surface44c, a second side surface44d, a third side surface44e, and a fourth side surface44f. The outer surface44ais a surface at the side opposite to the frame member43and the inner surface44bis a surface at the side of the frame member43. The outer surface44aand the inner surface44bextend in parallel to each other. Each of the side surfaces44cto44fextends in a direction perpendicular to the outer surface44aand the inner surface44band is continuous to the outer surface44aand the inner surface44b. The window member44is disposed on the frame member43so that the inner surface44bfaces the top surfaces51ato54a. The first side surface44c, the second side surface44d, the third side surface44e, and the fourth side surface44fare respectively located on the top surface51a, the top surface52a, the top surface53a, and the top surface54a.

The window member44includes a first corner portion61formed at the side of the first wall portion51by the outer surface44aand the first side surface44c, a second corner portion62formed at the side of the second wall portion52by the outer surface44aand the second side surface44d, a third corner portion63formed at the side of the third wall portion53by the outer surface44aand the third side surface44e, and a fourth corner portion64formed at the side of the fourth wall portion54by the outer surface44aand the fourth side surface44f. When viewed from the Z-axis direction, the first corner portion61overlaps the top surface51aand the second corner portion62overlaps the top surface52a. When viewed from the Z-axis direction, the third corner portion63overlaps the top surface53aand the fourth corner portion64overlaps the top surface54a. In this example, the first side surface44cis a flat surface, but the first side surface44cmay be a curved surface. In this case, the first corner portion61is formed at a boundary part between the flat outer surface44aand the curved first side surface44c. Similarly, the second side surface44dmay be a curved surface. In this case, the second corner portion62is formed at a boundary part between the flat outer surface44aand the curved second side surface44d.

A thickness T44of the window member44is thinner than each of a thickness T51of the first wall portion51, a thickness T52of the second wall portion52, a thickness T53of the third wall portion53, and a thickness T54of the fourth wall portion54. In this example, the thicknesses T51to T54of the wall portions51to54are the same. Further, the thickness T44of the window member44is smaller than a width W of a bonding region in which the window member44and the frame member43are bonded to each other by a bonding material45. The width W is a width in a direction parallel to each of the top surfaces51ato54aand orthogonal to the extension direction of the frame member43. In this example, the width W of the bonding region is the same along the entire periphery of the frame member43, but when the width of the bonding region changes in the circumferential direction of the frame member43, the width W is a maximum value of the width of the bonding region.

A positional relationship of respective members will be described with reference toFIGS. 2 and 3. The optical scanning device1is disposed, for example, so that the first axis X1is parallel to the X-axis direction and the second axis X2is parallel to the Y-axis direction.FIG. 2illustrates a cross-section parallel to both the X-axis direction and the Z-axis direction and passing through the center of the mirror surface7a. The cross-section ofFIG. 2is perpendicular to the Y-axis direction and is perpendicular to the first wall portion51and the second wall portion52.FIG. 3illustrates a cross-section parallel to both the Y-axis direction and the Z-axis direction and passing through the center of the mirror surface7a. The cross-section ofFIG. 3is perpendicular to the X-axis direction and is perpendicular to the third wall portion53and the fourth wall portion54.

FIGS. 2 and 3illustrate a non-rotation state (a non-drive state and an initial state) in which the movable portion10does not rotate around the first axis X1and the second axis X2. In the non-rotation state, the first movable portion3does not rotate around the first axis X1and the second movable portion4does not around the second axis X2. In the non-rotation state, the mirror surface7ais parallel to the main surface42aof the base42.

In the cross-section ofFIG. 2, a first line L1which passes through a first end P1corresponding to an end portion at the side of the first wall portion51in the mirror surface7aand a vertex of the first corner portion61intersects the first wall portion51. That is, the first line L1passes through the first wall portion51. Further, in the cross-section ofFIG. 2, a second line L2which passes through a second end P2corresponding to an end portion at the side of the second wall portion52in the mirror surface7aand a vertex of the second corner portion62intersects the second wall portion52. That is, the second line L2passes through the second wall portion52.

In the cross-section ofFIG. 3, a third line L3which passes through a third end P3corresponding to an end portion at the side of the third wall portion53in the mirror surface7aand a vertex of the third corner portion63intersects the third wall portion53. That is, the third line L3passes through the third wall portion53. Further, in the cross-section ofFIG. 3, a fourth line L4which passes through a fourth end P4corresponding to an end portion at the side of the fourth wall portion54in the mirror surface7aand a vertex of the fourth corner portion64intersects the fourth wall portion54. That is, the fourth line L4passes through the fourth wall portion54.

when the mirror surface7ais formed by mirror-finishing the surface of the first movable portion3, the end portion of the mirror surface7ais the end portion of the processed region. Alternatively, when a reflection film is not formed and the surface itself of the first movable portion3constitutes the mirror surface7a, the end portion of the mirror surface7ais the end portion of the first movable portion3. In the above-described embodiment, the first movable portion3is connected to the first connection portion5in a cross-section perpendicular to the Y-axis direction and passing through the center of the mirror surface7a. In this case, the end portion of the first movable portion3is located at a boundary part between the first movable portion3and the first connection portion5. As in the embodiment, when the first movable portion3includes the first portion31and the second portion32surrounding the first portion31and the mirror surface7ais provided on the first portion31, the end portion of the mirror surface7ais located in the vicinity of the end portion of the first portion31.

As illustrated inFIGS. 1 and 4, the mirror unit100further includes a wiring portion70electrically connected to the optical scanning device1. The wiring portion70includes a plurality of (eight in this example) inner electrode pads71, a plurality of (nine in this example) outer electrode pads72, and a plurality of (eight in this example) wirings73. Each of the inner electrode pad71, the outer electrode pad72, and the wiring73is formed of, for example, a metal material such as tungsten, aluminum, gold, silver, copper, or an aluminum-based alloy.

The inner electrode pad71is provided in an inner region (a first region) R1located at the inside of the frame member43when viewed from the Z-axis direction. The inner electrode pad71is disposed on the base42, more specifically, the bottom surface of the depression42c. The inner electrode pad71is disposed between the optical scanning device1and the third wall portion53on the bottom surface of the depression42c. In the mirror unit100, a distance C1between the optical scanning device1and the third wall portion53in the Y-axis direction is longer than a distance C2between the optical scanning device1and the fourth wall portion54in the Y-axis direction (FIG. 3). That is, the inner electrode pad71is disposed between the optical scanning device1and the third wall portion53which is distant from the optical scanning device1in the third wall portion53and the fourth wall portion54. In the mirror unit100, the distance between the optical scanning device1and the first wall portion51in the X-axis direction is the same as the distance between the optical scanning device1and the second wall portion52in the X-axis direction. The plurality of inner electrode pads71are arranged, for example, in the X-axis direction. Each of the plurality of inner electrode pads71is electrically connected to one of the electrode pads21a,21b,22a, and22bof the optical scanning device1through a wire WR.

The outer electrode pad72is provided in an outer region (a third region) R3located at the outside of the frame member43when viewed from the Z-axis direction. The outer electrode pad72is disposed on the base42, more specifically, the main surface42a. The plurality of outer electrode pads72are arranged at the same intervals, for example, in the X-axis direction. The plurality of outer electrode pads72are used in the electrical connection to, for example, an external control device or the like.

As illustrated inFIG. 1, the plurality of wirings73respectively electrically connect the inner electrode pad71and the outer electrode pad72to each other. The plurality of wirings73include a plurality of (four in this example) wirings73A and a plurality of (four in this example) wirings73B.

Each wiring73A is inclined with respect to the X-axis direction and the Y-axis direction when viewed from the Z-axis direction and extends in a linear shape. Each wiring73B has a plurality of (two in this example) bent portions. Each wiring73B includes a pair of first linear portions73Ba which are inclined with respect to the X-axis direction and the Y-axis direction when viewed from the Z-axis direction and extend in a linear shape and a second linear portion73Bb which extends in a linear shape in the X-axis direction when viewed from the Z-axis direction. The pair of first linear portions73Ba are located at both ends of the wiring73B and are connected to the second linear portion73Bb. The bent portions are formed at boundary parts between the pair of first linear portions73Ba and the second linear portion73Bb.

As illustrated inFIG. 4, each wiring73is disposed in a hole42eformed in the base42and extends inside the base42. Each wiring73is electrically connected to the inner electrode pad71in an inner region R1, extends inside the base42in an overlapping region (a second region) R2overlapping the frame member43when viewed from the Z-axis direction, and leads out to the outer region R3. That is, each wiring73includes a first portion74located in the inner region R1, a second portion75located in the overlapping region R2, and a third portion76located in the outer region R3.

The first portion74is connected to the inner electrode pad71. In this example, the wiring73and the inner electrode pad71are integrally formed (as a single member). In other words, the wiring73is provided to be exposed in the inner region R1and the exposed portion constitutes the inner electrode pad71. The second portion75is connected to the first portion74and extends in a linear shape below the third wall portion53. In other words, the wiring73extends inside the base42so as to overlap the third wall portion53when viewed from the Z-axis direction in the overlapping region R2. The third portion76is connected to the second portion75, leads out from the overlapping region R2to the outer region R3, and is connected to the rear surface of the outer electrode pad72. Although the wiring73A of the wiring73is illustrated inFIG. 4, the wiring73B also extends inside the base42similarly to the wiring73A.

Function and Effect

In the mirror unit100, a height H1of the first wall portion51is higher than a height H2of the second wall portion52and the window member44is disposed on the top surface51aof the first wall portion51and the top surface52aof the second wall portion52and is inclined with respect to the mirror surface7a. Accordingly, the traveling direction of the light reflected by the window member44can be different from the traveling direction of the light reflected by the mirror surface7aand the light reflected by the window member44can be prevented from to be noise light.

In a cross-section (FIG. 2) passing through the mirror surface7aand perpendicular to the first wall portion51, the first line L1passing through the first end P1at the side of the first wall portion51in the mirror surface7aand the first corner portion61formed at the side of the first wall portion51by the outer surface44aand the first side surface44cin the window member44intersects the first wall portion51. In the cross-section (FIG. 2), the second line L2passing through the second end P2at the side of the second wall portion52in the mirror surface7aand the second corner portion62formed at the side of the second wall portion52by the outer surface44aand the second side surface44din the window member44intersects the second wall portion52. In a cross-section (FIG. 3) passing through the mirror surface7aand perpendicular to the third wall portion53, the third line L3passing through the third end P3at the side of the third wall portion53in the mirror surface7aand the third corner portion63forming at the side of the third wall portion53by the outer surface44aand the third side surface44ein the window member44intersects the third wall portion53. In the cross-section (FIG. 3), the fourth line L4passing through the fourth end P4at the side of the fourth wall portion54in the mirror surface7aand the fourth corner portion64formed at the side of the fourth wall portion54by the outer surface44aand the fourth side surface44fof the window member44intersects the fourth wall portion54. Since the lines L1to L4are formed so as to intersect the wall portions51to54, each of the wall portions51to54is formed so as to be relatively thicker with respect to the window member44. Accordingly, it is possible to support the window member44by the thick wall portions51to54and to prevent the damage of the window member44.

Meanwhile, when the wall portions51to54are formed to be thick, it is conceivable to widen the thickness of the wall portions51to54toward the optical scanning device1from the viewpoint of miniaturization. However, in that case, the area of the portion located at the inside of the frame member43on the base42is narrowed. When a wiring portion for electrical connection to the optical scanning device1is formed in such a narrow portion, there is concern that defects such as short circuit or the like may occur in the wiring portion. In contrast, in the mirror unit100, the wiring portion70includes a portion (a wiring73) extending inside the base42and leads outside the frame member43. When the wiring portion70is formed inside the base42in this way, it is possible to prevent defects such as short circuit or the like in the wiring portion70. Further, for example, compared to a case in which the wiring portion70is formed so as to extend along the main surface42aof the base42between the base42and the frame member43, the deterioration of the wiring portion70can be prevented and the influence of the wiring portion70on the bonding portion (the bonding material46) between the base42and the frame member43can be prevented. Thus, according to the mirror unit100, it is possible to prevent the damage of the window member44while reducing noise light and to improve reliability.

The thickness T44of the window member44is smaller than the width W in which the window member44and the frame member43are bonded to each other. Accordingly, the window member44can be formed to be thin and the influence of refraction at the window member44can be refrained.

The first line L1intersects the first wall portion51and the second line L2intersects the second wall portion52. Accordingly, since both the first wall portion51and the second wall portion52facing each other are formed to be relatively thicker with respect to the window member44, it is possible to support the window member44by the thick wall portions51and52and to further reliably prevent the damage of the window member44. Further, the third line L3intersects the third wall portion53and the fourth line L4intersects the fourth wall portion54. Accordingly, since both the third wall portion53and the fourth wall portion54facing each other are formed to be thicker than the window member44, it is possible to support the window member44by the thick wall portions53and54and to further reliably prevent the damage of the window member44.

The wiring portion70extends inside the base42so as to overlap the third wall portion53when viewed from the Z-axis direction in the overlapping region R2. When the wiring portion70is to be pulled out toward the thick third wall portion53, the above-described deterioration of the wiring portion70is likely to occur. However, in the mirror unit100, since the wiring portion70is formed inside the base42, deterioration of the wiring portion70or the like can be reliably prevented.

A distance C1between the optical scanning device1and the third wall portion53is longer than a distance C2between the optical scanning device1and the fourth wall portion54and the inner electrode pad71is disposed between the optical scanning device1and the third wall portion53on the base42. Accordingly, it is possible to ensure a space for disposing the inner electrode pad71.

The wiring portion70is electrically connected to the optical scanning device1in the inner region R1located at the inside of the frame member43when viewed from the Z-axis direction, extends inside the base42in the overlapping region R2overlapping the frame member43when viewed from the Z-axis direction, and leads out to the outer region R3located at the outside of the frame member43when viewed from the Z-axis direction. Accordingly, it is possible to further reliably prevent deterioration of the wiring portion70or the like.

The wiring portion70does not include a portion formed on the rear surface42bof the base42. When the rear surface42bof the base42is fixed to an upper surface of a magnet (a magnetic field generating unit) by adhering, it is preferable that the base42be as close as possible to the magnet in order to ensure magnetic force acting on the first drive coil11and the second drive coil12. Since the wiring portion70does not include a portion formed on the rear surface42bof the base42, the base42can be close to the magnet and hence large magnetic force acting on the first drive coil11and the second drive coil12can be ensured.

Modified Example

In a wiring portion70A illustrated inFIG. 6, the outer electrode pad72and the wiring73are provided in the inner region R1. The outer electrode pad72is disposed on the rear surface42bof the base42in the inner region R1. The wiring73is connected to the rear surface of the inner electrode pad71, extends inside the base42in a linear shape in the Z-axis direction, and is connected to the rear surface of the outer electrode pad72. Also in such a modified example, deterioration of the wiring portion70or the like can be prevented similarly to the above-described embodiment.

In the modified example, the outer electrode pad72may be disposed on the rear surface42bof the base42in the outer region R3. In this case, the wiring73may include a first portion which is connected to the rear surface of the inner electrode pad71, extends inside the base42in a linear shape in the Z-axis direction, and is exposed to the rear surface42bof the base42and a second portion which is connected to the first portion, is provided on the rear surface42bso as to extend over the inner region R1, the overlapping region R2, and the outer region R3, and is connected to the outer electrode pad72.

In the modified example, the outer electrode pad72may be disposed on the main surface42aof the base42in the outer region R3. In this case, the wiring73may include a first portion which is connected to the rear surface of the inner electrode pad71, extends inside the base42in a linear shape in the Z-axis direction, and is exposed to the rear surface42bof the base42, a second portion which is connected to the first portion and is provided on the rear surface42bso as to extend over the inner region R1, the overlapping region R2, and the outer region R3, and a third portion which is connected to the second portion, extends inside the base42in a linear shape in the Z-axis direction, and is connected to the rear surface of the outer electrode pad72.

The present disclosure is not limited to the embodiment and the modified example above. For example, the materials and shapes of the components are not limited to the materials and shapes described above and various materials and shapes can be adopted. The thicknesses T51to T54of the wall portions51to54may be different from each other. The wiring73may be electrically connected to the inner electrode pad71in the inner region R1, extend inside the base42in the overlapping region R2, and lead out to the outer region R3and a part of the wiring73may be configured as a surface wiring formed along the surface of the base42. In the optical scanning device1of the embodiment, the movable portion10is driven by the electromagnetic force, but the movable portion10may be driven by an electrostatic force or a piezoelectric element.

In the above-described embodiment, the third wall portion53can be regarded as a first reference wall portion and the fourth wall portion54can be regarded as a second reference wall portion. In this case, the third wall portion53, the third end P3, the third side surface44e, the third corner portion63, and the third line L3respectively correspond to the first wall portion, the first end, the first side surface, the first corner portion, and the first line and the fourth wall portion54, the fourth end P4, the fourth side surface44f, the fourth corner portion64, and the fourth line L4respectively correspond to the second wall portion, the second end, the second side surface, the second corner portion, and the second line. In the above-described embodiment, the third wall portion53can be regarded as the second reference wall portion and the fourth wall portion54can be regarded as the third reference wall portion.

In the above-described embodiment, the first wall portion51can be regarded as the first reference wall portion and the second wall portion52can be regarded as the second reference wall portion. In this case, the first wall portion51, the first end P1, the first side surface44c, the first corner portion61, and the first line L1respectively correspond to the first wall portion, the first end, the first side surface, the first corner portion, and the first line and the second wall portion52, the second end P2, the second side surface44d, the second corner portion62, and the second line L2respectively correspond to the second wall portion, the second end, the second side surface, the second corner portion, and the second line. In this case, the distance between the optical scanning device1and the first wall portion51may be longer than the distance between the optical scanning device1and the second wall portion52and the inner electrode pad71may be disposed between the optical scanning device1and the first wall portion51on the base42. That is, the inner electrode pad71may be disposed between the optical scanning device1and the first wall portion51distant from the optical scanning device1in the first wall portion51and the second wall portion52. Also in this case, it is possible to ensure a space for disposing the inner electrode pad71. Further, since the first wall portion51is separated from the optical scanning device1compared to the second wall portion52, it is possible to prevent the light reflected by the mirror surface7afrom being interrupted by the first wall portion51higher than the second wall portion52. In the above-described embodiment, the first wall portion51can be regarded as the second reference wall portion and the second wall portion52can be regarded as the first reference wall portion.

In the above-described embodiment, all of the conditions (1) to (4) below are met. However, at least one of the conditions (1) to (4) below may be met and the others may not be met.

(1) In the cross-section ofFIG. 2, the first line L1intersects the first wall portion51.

(2) In the cross-section ofFIG. 2, the second line L2intersects the second wall portion52.

(3) In the cross-section ofFIG. 3, the third line L3intersects the third wall portion53.

(4) In the cross-section ofFIG. 3, the fourth line L4intersects the fourth wall portion54.

The window member44may be provided with a notch. The notch may be formed in, for example, the outer surface44aand may extend along the edge portion of the outer surface44a. The notch may be formed in, for example, a rectangular cross-sectional shape. In this case, the window member44includes a first corner portion formed at the side of the first wall portion51by the outer surface44aand the inner surface of the notch, a second corner portion formed at the side of the second wall portion52by the outer surface44aand the inner surface of the notch, a fifth corner portion (another first corner portion) formed by the inner surface of the notch and the first side surface44c, and a sixth corner portion (another second corner portion) formed by the inner surface of the notch and the second side surface44din the cross-section ofFIG. 2. Further, the window member44includes a third corner portion formed at the side of the third wall portion53by the outer surface44aand the inner surface of the notch, a fourth corner portion formed at the side of the fourth wall portion54by the outer surface44aand the inner surface of the notch, a seventh corner portion (another third corner portion) formed by the inner surface of the notch and the third side surface44e, and an eighth corner portion (another fourth corner portion) formed by the inner surface of the notch and the fourth side surface44fin the cross-section ofFIG. 3. In this case, at least one of the conditions (5) to (8) below may be met. (5) In the cross-section ofFIG. 2, a line passing through the first corner portion and the first end P1at the side of the first wall portion51in the mirror surface7aintersects the first wall portion51. (6) In the cross-section ofFIG. 2, a line passing through the second corner portion and the second end P2at the side of the second wall portion52in the mirror surface7aintersects the second wall portion52. (7) In the cross-section ofFIG. 3, a line passing through the third corner portion and the third end P3at the side of the third wall portion53in the mirror surface7aintersects the third wall portion53. (8) In the cross-section ofFIG. 3, the fourth line L4passing through the fourth corner portion and the fourth end P4at the side of the fourth wall portion54in the mirror surface7amay intersect the fourth wall portion54. Accordingly, similarly to the above-described embodiment, each of the wall portions51to54can be formed to be thick. At least one of the conditions (9) to (12) below may be met. (9) In the cross-section ofFIG. 2, a line passing through the first end P1and the fifth corner portion intersects the first wall portion51. (10) In the cross-section ofFIG. 2, a line passing through the second end P2and the sixth corner portion intersects the second wall portion52. (11) In the cross-section ofFIG. 3, a line passing through the third end P3and the seventh corner portion intersects the third wall portion53. (12) In the cross-section ofFIG. 3, a line passing through the fourth end P4and the eighth corner portion intersects the fourth wall portion54. Also in this condition, each of the wall portions51to54can be formed to be thick. When the conditions (9) to (12) above are met, the conditions (5) to (8) above may not be met. In this case, since the conditions (9) to (12) above are met, each of the wall portions51to54can be formed to be thick. Further, since the conditions (5) to (8) above are not met, it is possible to prevent the light reflected by the mirror surface7afrom being interrupted by each of the wall portions51to54and to use the entire outer surface44aof the window member44for optical scanning. The outer surface44aof the window member44means a surface facing the side opposite to the optical scanning device1and includes the inner surface of the notch.