JP7108477B2 - optical deflector - Google Patents

Description

The present invention relates to a piezoelectrically driven optical deflector.

Conventionally, in order to scan laser light with a scanner or pico-projector, the mirror section is rotated back and forth around the rotation axis, and the incident light from the light source is reflected by the mirror section and emitted. Deflectors are known.

For example, the piezoelectric actuator disclosed in Patent Document 1 below includes, in order from the bottom, a Si layer as a substrate, a _SiO2 layer as an interlayer insulating film, a Ti layer as an electrode adhesion film, a Pt layer as a lower electrode film, and a piezoelectric film as a It has a PZT layer, a Pt layer as an upper electrode film, a Ti layer as an electrode adhesion film, and a SiN layer as a passivation film (paragraph 0061, FIG. 7).

Here, the passivation film (nitride film) has a structure to cover and protect the top and side surfaces of the wiring, piezoelectric film, etc., in order to prevent the wiring from corroding due to humidity and temperature.

JP 2015-169745 A

However, the substrate surface (for example, Si active layer, etc.) with which the nitride film is in contact tends to have poor adhesion with the nitride film. In particular, when the wiring is passed through a portion where the width is reduced and torsional stress is applied structurally, displacement in the rotational direction occurs due to the torsional stress, so cracking and peeling due to the nitride film are likely to occur. .

In the optical deflector of Patent Document 1, if the wiring of the horizontal scanning sensor of the mirror section is damaged, the signal cannot be extracted from the sensor with high accuracy, and the deflection angle of the mirror section cannot be accurately controlled. rice field.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical deflector that suppresses the occurrence of cracking and peeling of wiring in a portion to which stress is applied.

An optical deflector according to a first aspect of the invention comprises a mirror portion that reflects light, a frame that surrounds the mirror portion and has a double structure of an inner frame and an outer frame, and the mirror portion. a pair of torsion bars, one end of which is coupled to the mirror portion and the other end of which is coupled to the frame, a support for supporting the frame, and the torsion bar on a first axis passing through the center of the a first piezoelectric actuator having a bar reciprocatingly rotated around the first axis and at least a portion of which is coupled to the frame; A piezoelectric sensor that detects voltage, and an optical deflector comprising:
A first extending portion extending from the other end side of the torsion bar to the outer end of the frame along the first axis of the frame has a laminated structure in which thin films are laminated, Wiring connected to the piezoelectric sensor or the first piezoelectric actuator and extending to the support through the first extending portion, and a connection portion connecting the inner frame and the outer frame are provided. ,
The laminated structure includes an insulating film formed on one side of a substrate constituting the frame, an interlayer film formed on the upper surface of the insulating film, an electrode film formed on the upper surface of the interlayer film, and the electrode film. It has an outer layer film covering it, and at least at the connecting portion , the wiring is formed so that the outer layer film does not come into contact with the substrate .

The optical deflector of the present invention drives the first piezoelectric actuator to reciprocate the torsion bar about the first axis, thereby operating the mirror section coupled with the torsion bar. Accordingly, the mirror section can reflect light from a semiconductor laser or the like in various directions. At this time, since the piezoelectric sensor detects the amount of deformation of the first piezoelectric actuator, it is possible to acquire the deflection angle of the mirror section.

The wiring connected to the piezoelectric sensor has a laminated structure consisting of an insulating film formed on one side of the frame, an interlayer film on the upper surface side, an electrode film on the upper surface side, and an outer layer film covering the electrode film. is a first extending portion extending along the first axis from the region on the other end side of the torsion bar to the outer end of the frame, particularly the connecting portion connecting the inner frame and the outer frame is formed so that the outer layer film of the wiring does not come into contact with the substrate .

The insulating film can ensure higher adhesion than the outer layer film, and is less likely to peel off even when stress occurs. As a result, it is possible to suppress the occurrence of cracking and peeling due to the outer layer film of the first extending portion.

Further, in the optical deflector of the first invention, the wiring extending from the first extending portion in a direction along the shape of the outer frame is formed so that the outer layer film does not come into contact with the substrate . is preferred.

Since the wiring of the piezoelectric sensor extends from the first extending portion in the direction along the shape of the outer frame, the wiring includes wiring in a direction different from the first axis. In the present invention, even if the wiring is in a direction different from the first axis of the first extending portion, it is formed so that the outer layer film does not come into contact with the substrate . Thereby, the reliability of wiring can be further improved.

Further, in the optical deflector of the first invention, a second piezoelectric actuator for reciprocatingly rotating the mirror portion around a second axis line passing through the center of the mirror portion and perpendicular to the first axis line on the same plane. In the second piezoelectric actuator, a plurality of piezoelectric cantilevers are arranged side by side on the second axis so that the longitudinal directions of the piezoelectric cantilevers are adjacent to each other, and one end of the piezoelectric cantilever is mechanically bent so as to fold back with respect to the adjacent piezoelectric cantilevers. is preferably connected to

A second piezoelectric actuator that reciprocates the mirror portion about the second axis is composed of a plurality of piezoelectric cantilevers. Since the piezoelectric cantilevers are arranged side by side on the second axis so that the longitudinal direction of the piezoelectric cantilevers are adjacent to each other, each piezoelectric cantilever bends and deforms around the second axis when a voltage is applied.

In addition, since one end portion is mechanically connected to the adjacent piezoelectric cantilever so as to be folded back, bending deformation can be accumulated and the rotation of the mirror portion can be increased. Accordingly, it is possible to realize an optical deflector that can two-dimensionally scan light by driving the first and second piezoelectric actuators.

An optical deflector according to a second aspect of the invention comprises a mirror portion that reflects light, a frame surrounding the mirror portion and having a double structure of an inner frame and an outer frame, and the mirror portion. a pair of torsion bars having one end coupled to the mirror portion and the other end coupled to the frame on a first axis passing through the center of the torsion bar reciprocating around the first axis A first piezoelectric actuator that rotates and at least a portion of which is coupled to the frame, and the mirror section around a second axis passing through the center of the mirror section and perpendicular to the first axis on the same plane. A second piezoelectric actuator for reciprocating rotation , and a piezoelectric sensor for detecting a voltage corresponding to the amount of deformation of the first piezoelectric actuator ,
In the second piezoelectric actuator, a plurality of piezoelectric cantilevers are arranged side by side on the second axis so that the longitudinal directions of the piezoelectric cantilevers are adjacent to each other, and one end is mechanically connected to the adjacent piezoelectric cantilevers so as to be folded back. an optical deflector comprising:
A second extending portion extending from the outer end of the inner frame along the second axis of the frame to the piezoelectric cantilever closest to the frame constituting the second piezoelectric actuator includes a laminated thin film. having a wiring connected to the piezoelectric sensor, the first piezoelectric actuator, or the second actuator,
When the second extending portion does not have the piezoelectric film and the electrode film of the piezoelectric film, and only the wiring exists, the laminated structure includes an insulating film formed on one side of the substrate constituting the frame, the an interlayer film formed on an upper surface of an insulating film; an electrode film formed on an upper surface of the interlayer film; is formed so as not to come into contact with the substrate .

In the optical deflector of the second aspect of the invention, the second extending portion extending along the second axis from the outer end of the inner frame to the piezoelectric cantilever closest to the frame constituting the second piezoelectric actuator includes: This is the portion with the largest displacement when the second piezoelectric actuator is driven. Therefore, by forming the outer layer film of the wiring connected to the piezoelectric sensor, the first piezoelectric actuator, or the second actuator so as not to contact the substrate in the second extending portion , the reliability of the wiring can be improved.

An optical deflector according to a third aspect of the invention comprises a mirror portion that reflects light, a frame that surrounds the mirror portion, and one end of which is positioned on a first axis passing through the center of the mirror portion. a pair of torsion bars connected to the frame and having the other end connected to the frame, the torsion bars reciprocally rotating about the first axis, and at least a portion of the torsion bar being connected to the frame a first piezoelectric actuator, a second piezoelectric actuator for reciprocally rotating the mirror section about a second axis passing through the center of the mirror section and perpendicular to the first axis on the same plane, and the first piezoelectric a piezoelectric sensor that detects a voltage corresponding to the amount of deformation of the actuator , wherein the second piezoelectric actuator has a plurality of piezoelectric cantilevers arranged side by side on the second axis such that the longitudinal direction of the piezoelectric cantilevers is adjacent to each other. and one end of the optical deflector is mechanically connected to the adjacent piezoelectric cantilever so as to be folded back,
further comprising a wiring configured with a laminated structure in which thin films are laminated and connected to the piezoelectric sensor, the first piezoelectric actuator or the second actuator,
When the piezoelectric film and the electrode film of the piezoelectric film do not exist in the folded portion of the piezoelectric cantilever and only the wiring exists, the laminated structure is an insulating film formed on one side of the substrate constituting the folded portion of the piezoelectric cantilever. an interlayer film formed on the upper surface of the insulating film; an electrode film formed on the upper surface of the interlayer film; and an outer layer film covering the electrode film. The outer layer film is formed so as not to contact the substrate .

In the optical deflector of the third invention, when the wiring connected to the piezoelectric sensor, the first piezoelectric actuator or the second actuator passes through the folded portion of the piezoelectric cantilever of the second piezoelectric actuator, the outer layer film of the wiring does not contact the substrate . form like Thereby, the reliability of wiring can be further improved.

FIG. 2 is a configuration diagram of an optical scanner module; 1 is a perspective view of an optical deflector of the present invention; FIG. FIG. 4 is a diagram for explaining the operation of the bellows-shaped piezoelectric actuator (before driving); FIG. 4 is a diagram for explaining the operation of the bellows-shaped piezoelectric actuator (after driving); FIG. 3 is an enlarged view of a region R (a portion where a piezoelectric sensor is arranged) in FIG. 2; Sectional drawing of signal wiring (conventional example). FIG. 5 is a VV cross-sectional view of the signal wiring in FIG. 4; An enlarged view (1) of an optical deflector with a part of the piezoelectric film removed. An enlarged view (2) of the optical deflector from which a part of the piezoelectric film is removed. FIG. 5 is a diagram showing the result of a driving test of the mirror section; FIG. 5 is a diagram for explaining a configuration in which wiring passes through a region U';

First, the configuration of the optical scanner module will be described with reference to FIG.

The optical scanner module 1 is a component used in, for example, a pico projector, LiDAR (Light Detection and Landing), headlamp, etc., and is mainly composed of an optical deflector 2 , a laser light source 3 and a control device 5 .

The optical deflector 2 of the embodiment of the present invention is manufactured using a semiconductor process or MEMS (Micro Electro Mechanical Systems) technology, reflects light incident from a fixed direction on a rotating micromirror, and emits it as scanning light. do.

A movable frame 8 (“frame body” of the present invention), which is an inner frame of the optical deflector 2, is provided with a mirror portion 9, a piezoelectric actuator 10, a torsion bar 13, and the like. The laser light 4a incident from the laser light source 3 is reflected by the mirror portion 9, and the reflected light (laser light 4b) scans, for example, the projection surface of the pico-projector.

At this time, the control device 5 transmits control signals to the movable frame 8 and the laser light source 3 . The piezoelectric actuator 10 in the movable frame 8 is driven by this control signal, and the torsion bar 13 connected thereto is twisted, thereby rotating the mirror portion 9 . Also, the laser light 4a of the laser light source 3 is controlled in on/off and brightness by a control signal.

Next, the details of the optical deflector will be described with reference to FIG.

In the initial state, the mirror section 9 is arranged so that the normal extending from the center O toward the front side faces straight forward in the optical deflector 2 . The mirror portion 9 is supported by a torsion bar 13 in the Y-axis (“first axis” of the present invention) direction and arranged at the center of the movable frame 8 .

The reflecting surface of the mirror section 9 is formed by forming a metal thin film of Au, Pt, Al, or the like, for example, by sputtering or electron beam vapor deposition. Note that the shape of the mirror portion 9 is not limited to a circle, and may be oval or other shapes.

As illustrated, the movable frame 8 has a double structure of an inner frame 8a and an outer frame 8b. The piezoelectric actuator 10 includes a semi-annular piezoelectric actuator 10a on the left side when viewed from the front and a semi-annular piezoelectric actuator 10b on the right side when viewed from the front, and is formed on the upper surface of the inner frame 8a. That is, the inner frame 8a is an annular driving portion in which a plurality of piezoelectric portions are arranged in a ring. The semi-annular piezoelectric actuators 10a, 10b can, for example, consist of three parts arranged side by side.

The torsion bar 13 is composed of an upper torsion bar 13a in front view and a lower torsion bar 13b in front view. The torsion bars 13a and 13b are connected to the mirror portion 9 at one end and to the inner frame 8a at the other end. By connecting the torsion bars 13a and 13b in this manner, the reciprocating rotation of the mirror portion 9 in the Y-axis direction is stabilized.

An inner frame 8a having semi-annular piezoelectric actuators 10a and 10b (“first piezoelectric actuators” of the present invention) is arranged to surround the mirror portion 9 from the outside. An inner frame 8a with semi-annular piezoelectric actuators 10a, 10b is coupled on the Y-axis with torsion bars 13a, 13b and also with an outer frame 8b.

The semi-annular piezoelectric actuators 10a and 10b have a structure in which a piezoelectric film of lead zirconate titanate (PZT) is sandwiched between a lower electrode and an upper electrode by a semiconductor process. By applying a voltage to the piezoelectric film via the lower electrode and the upper electrode, the semi-annular piezoelectric actuators 10a and 10b are bent and deformed to twist the torsion bars 13a and 13b.

In the optical deflector 2, a movable frame 8 is disposed in the center of an outer frame support 11, and bellows-shaped piezoelectric actuators 6a and 6b ("second piezoelectric actuators" of the present invention) are provided on both sides of the movable frame 8. are placed. The bellows-shaped piezoelectric actuators 6a and 6b are connected to the ends of the outer frame 8b (region S) and the outer frame support 11 on the X- axis (the "second axis" of the present invention) . , the inner frame 8a and the outer frame 8b are connected.

Although details will be described later, each of the bellows-shaped piezoelectric actuators 6a and 6b has a structure in which a plurality of cantilevers are arranged side by side in the longitudinal direction, folded back at the ends in the vertical direction, and connected in series. By driving the bellows-shaped piezoelectric actuators 6a and 6b, the movable frame 8 reciprocates around the X axis.

As a result, when the laser beam 4a is reflected by the mirror portion 9, the optical deflector 2 emits the light in front of the optical deflector 2, and further scans in two directions of the X-axis direction and the Y-axis direction. can.

Electrode pads 7a-1 to 7a-8 (hereinafter referred to as electrode pads 7a) are arranged on the left side of the outer frame support 11 in front view, and electrode pads b- 1 to 7b-8 (hereinafter referred to as electrode pads 7b) are provided. The electrode pads 7a and 7b are electrically connected so as to apply a drive voltage to each electrode of the bellows-shaped piezoelectric actuators 6a and 6b and the semi-circular piezoelectric actuators 10a and 10b.

Next, the operation of the bellows-shaped piezoelectric actuator will be described with reference to FIGS. 3A and 3B.

As described above, the optical deflector 2 of the embodiment enables the mirror section 9 to reciprocate in the X-axis direction by operating the bellows-shaped piezoelectric actuators 6a and 6b.

FIG. 3A is a cutout view of the bellows-shaped piezoelectric actuator 6a arranged on the left side when the optical deflector 2 is viewed from the front side. The bellows-shaped piezoelectric actuator 6a has a shape in which five piezoelectric cantilevers are arranged. Each piezoelectric cantilever is mainly composed of a piezoelectric film and electrode films sandwiching it. Hereinafter, the piezoelectric cantilevers 6a(1), 6a(2), 6a(3), 6a(4), and 6a(5) are referred to in order from the side remote from the movable frame 8. FIG.

For example, in the bellows-shaped piezoelectric actuator 6a, a first voltage is applied to the odd-numbered piezoelectric cantilevers 6a(1), 6a(3), and 6a(5). A second voltage having a phase opposite to that of the first voltage is applied to the even-numbered piezoelectric cantilevers 6a(2) and 6a(4).

By doing so, as shown in FIG. 3B, the odd-numbered piezoelectric cantilevers 6a(1), 6a(3), and 6a(5) are bent downward, and the even-numbered piezoelectric cantilever 6a(2) is bent downward. , 6a(4) can be bent upward. The piezoelectric cantilever 6a(1) has the widest width among the five piezoelectric cantilevers and is connected to the outer frame support 11, so that it hardly bends.

Although not shown, the bellows-shaped piezoelectric actuator 6b is referred to as piezoelectric cantilevers 6b(1), 6b(2), 6b(3), 6b(4), and 6b(5) in order from the side closest to the movable frame 8. FIG. At this time, the odd-numbered piezoelectric cantilevers 6b(1), 6b(3), 6b(5) are bent downward, and the even-numbered piezoelectric cantilevers 6b(2), 6b(4) are bent upward. can be made

As a result, the mirror portion 9 is arranged such that the upper side (torsion bar 13a side) of the mirror portion 9 is lower than the lower side (torsion bar 13b side) of the mirror portion 9 (the upper side moves in the Z-axis direction in the drawing). can be displaced. In this manner, the mirror section 9 can be set at various angles in the X-axis direction.

Next, a piezoelectric sensor that detects the deflection angle of the mirror portion will be described with reference to FIG. FIG. 4 is an enlarged view of region R in FIG.

The piezoelectric sensors 30a and 30b are horizontal scanning sensors (H sensors), and are arranged at positions straddling the joints between the torsion bar 13b and the semi-annular piezoelectric actuators 10a and 10b.

From the piezoelectric sensor 30a and the piezoelectric sensor 30b, substantially the same numerical values can be obtained although the phases are different. At least one piezoelectric sensor can detect the distortion of the semi-annular piezoelectric actuators 10a and 10b.

The piezoelectric sensors 30a and 30b detect voltage corresponding to the displacement of the inner frame 8a, which includes the semi-annular piezoelectric actuator 10a made up of a plurality of piezoelectric portions. As a result, the deflection angle of the mirror section 9 can be detected without phase delay.

The displacement of the inner frame 8a is sent from the signal wiring 32a connected to the piezoelectric sensor 30a to one of the electrodes forming the electrode pad 7b. The displacement of the inner frame 8a is also sent to one of the electrodes forming the electrode pad 7b from the signal wiring 32b connected to the piezoelectric sensor 30b.

The signal wirings 32a and 32b extend in one direction along the shape of the outer frame 8b, and extend from the portion (region S in FIG. 2) connecting the outer frame 8b and the bellows-like piezoelectric actuator 6b to the bellows-like piezoelectric actuator 6b. is connected to the electrode pad 7b through the wiring layer of the laminated structure. The lower electrodes constituting the piezoelectric sensors 30a and 30b are continuous films integral with the lower electrodes of the semi-annular piezoelectric actuators 10a and 10b and are grounded (common GND).

Sensor signals from the piezoelectric sensors 30a and 30b are sent to the controller 5 (see FIG. 1) via the electrode pads 7b. As a result, the control device 5 can control the deflection angle of the mirror section 9 by feeding it back in real time.

Here, regarding the region U (“first extension portion” in the present invention) extending from the torsion bar 13b beyond the inner frame 8a to the outer frame 8b, when the mirror portion 9 rotates, the maximum This is the part where stress is applied. Furthermore, the outer layer film (SiN layer) that protects the signal wirings 32a and 32b has low adhesion to the Si active layer on the substrate surface. Although the details will be described later, the outer layer film does not cover the substrate surface (Si active layer) so as not to cause disconnection due to the peeling of the wiring at this portion. That is, the outer layer film and the substrate surface (Si active layer) are separated from each other.

Next, with reference to FIGS. 5A and 5B, the cross-sectional structure of the signal wiring will be described.

First, FIG. 5A shows a cross-sectional structure of a conventional signal wiring (referred to as signal wiring 31). The signal wiring 31 comprises, in order from the bottom, a substrate 20 (the surface is a Si active layer), a _SiOx layer 22 as a thermally oxidized insulating film (the "insulating film" of the present invention), a SiN layer 24 as an interlayer film, and an electrode film for wiring. and an SiN layer 28 as an outer layer film (passivation film) that covers and protects the wiring layer. 4, the substrate 20 is a portion where structures such as piezoelectric actuators and piezoelectric sensors are not formed.

As shown, the SiN layer 28 is formed so as to cover not only the AlNd layer 26 but also the top and side surfaces of the SiN layer 24, the side surfaces of the _SiOx layer 22, and the top surface of the Si active layer of the substrate 20. . As described above, in addition to the low adhesion between the SiN layer 28 and the Si active layer of the substrate 20, the width of the wiring is reduced in the region U, and torsional stress is generated by the torsion bar 13b. Cheap.

Next, FIG. 5B shows a cross-sectional (VV cross section) structure of the signal wiring 32a of FIG. It is the same in that the signal wiring 32a has the substrate 20 (Si active layer), the _SiOx layer 22, the SiN layer 24, the AlNd layer 26, and the SiN layer 28 in order from the bottom. However, in the present invention, only the signal wirings 32a and 32b in the region U (including part of the signal wirings along the shape of the outer frame 8b) are dry-etched for the portion where the SiN layer 28 is in direct contact with the Si active layer. are removed by , leaving both films separated from each other.

Only the etching pattern in the dry etching process is different from the conventional one, and the number of processes is not increased. Since it is sufficient that the SiN layer 28 does not come into direct contact with the Si active layer, the side surface of the _SiOx layer 22 may be partially covered. An intervening layer having good adhesion to the SiN layer 28 may be formed on the upper surface of the substrate 20 (Si active layer) so that the SiN layer 28 and the Si active layer do not come into direct contact with each other.

Since the _SiOx layer 22 is usually formed by oxidizing Si at a high temperature, it is possible to ensure higher adhesion than the SiN layer 28 formed by plasma CVD or the like, and peeling does not occur even when stress occurs. unlikely to occur. As a result, crack separation between the Si active layer and the SiN layer 28 can be suppressed, so sensor signals of the piezoelectric sensors 30a and 30b can be extracted with high accuracy, and the mirror section 9 can be controlled accurately.

Although the SiN layer 28 does not cover the Si active layer of the substrate 20 for the signal wirings 32a and 32b in the region U this time, it is not limited to this. The signal wires 32a and 32b pass through the region S in FIG. 2 and are routed in the direction of the electrode pad 7b. The region S on the X-axis is a portion where the displacement caused by the bellows-shaped piezoelectric actuator 6b is large.

FIG. 6A shows a portion corresponding to the region S in FIG. 2 in the optical deflector from which the piezoelectric film of the portion connecting the movable frame 8 and the bellows-shaped piezoelectric actuator 6b is removed. The signal wirings 32a, 32b and the wirings 33 in this region (the “second extending portion” of the present invention) may also have a structure in which the SiN layer 28 does not cover the Si active layer of the substrate 20. FIG. Thereby, the reliability of the signal wiring can be further improved.

In addition, although the area T in FIG. 2 is covered with the piezoelectric film up to the folded portions of the bellows-shaped piezoelectric actuators 6a and 6b, the piezoelectric film in this portion is not essential. FIG. 6B shows a portion corresponding to the region T in FIG. 2 in the optical deflector in which the piezoelectric film of the folding portion of the bellows-shaped piezoelectric actuator 6a is removed. In this region (the “turned-back portion” of the present invention), wirings for applying a driving voltage to the bellows-shaped piezoelectric actuator 6a and wirings for outputting a detection voltage of the piezoelectric sensor (wirings 34a to 34d) are provided. A structure in which the SiN layer 28, which is the outer layer film of the wiring, does not cover the Si active layer of the substrate 20 may be employed.

Next, with reference to FIG. 7, test results are shown in which the mirror portion of the optical deflector is driven and the conventional signal wiring structure and the structure of the present invention are compared.

First, when the mirror section was driven for 12 hours with a deflection angle of ±13° depending on the resonance frequency, no peeling of the outer layer film (SiN layer) occurred in both the conventional structure of the signal wiring and the structure of the present invention. .

On the other hand, when the mirror section was driven for 12 hours with the deflection angle of ±18° depending on the resonance frequency, the signal wiring of the present invention did not peel, but the signal wiring of the conventional structure did. As a result, it was confirmed that the signal wiring structure of the present invention has a certain level of reliability.

The above-described embodiment is merely an example, and various modifications are conceivable. The laminated structure of the signal wirings 32a and 32b is an example, and electrode adhesion films and interlayer insulating films may be provided as appropriate.

In FIG. 4, the signal wirings 32a and 32b are both routed to the right, but they may be routed to the left or may be divided into left and right. Further, the positions of the piezoelectric sensors 30a and 30b are not limited to the torsion bar 13b side, and may be on the torsion bar 13a side.

In the above-described embodiment, the signal wiring of the piezoelectric sensor is mainly structured so that the SiN layer does not cover the Si active layer of the substrate. is the same. The wiring of the piezoelectric actuator passes through the regions S and T (see FIG. 2), and in some cases also passes through the region U (see FIG. 4). do it.

For example, FIG. 8 shows a configuration in which wiring for applying drive voltages to piezoelectric actuators passes through region U'. It should be noted that the wiring in the drawing is actually arranged in the lower layer of the piezoelectric film (patterned portion).

A region U' is a position symmetrical to the region U described above, that is, a region extending from the torsion bar 13a beyond the inner frame 8a to the outer frame 8b. As described above, the wirings 35a and 35b of the piezoelectric actuator passing through the region U' are formed on one side of the movable frame 8 in the same manner as the signal wiring 36 of the piezoelectric sensor.

The wirings 35a and 35b are composed of a _SiOx layer as a thermally oxidized insulating film (the "insulating film" of the present invention), a SiN layer as an interlayer film, an AlNd layer as an electrode film for wiring, and a It has a laminated structure consisting of a SiN layer as an outer layer film (passivation film) that covers and protects the wiring layer. The wirings 35a and 35b have a structure in which the SiN layer of the outer layer film does not cover the movable frame 8 (the Si active layer of the substrate 20).

Regions S and S' and regions T and T' in the figure (especially when the frame and the folded portion of the piezoelectric cantilever are not covered with the piezoelectric film) are similarly the outer layer film of the wiring of the piezoelectric actuator. Alternatively, by forming the folded portion of the piezoelectric cantilever so as not to cover it, it is possible to manufacture an optical deflector that suppresses cracking and peeling of the wiring caused by the nitride film.

REFERENCE SIGNS LIST 1 optical scanner module 2 optical deflector 3 laser light source 4a, 4b laser light 5 controller 6a, 6b accordion-shaped piezoelectric actuator 7a1 to 7a8, 7b1 to 7b8 electrode pad 8 Movable frame 8a Inner frame 8b Outer frame 9 Mirror section 10a, 10b Semi-annular piezoelectric actuator 11 Outer frame support 13a, 13b Torsion bar 20 Substrate 22 SiO _x layer 24 SiN layer 26 AlNd layer 28 SiN layer 30a, 30b piezoelectric sensor 31, 32a, 32b, 36 signal wiring 33, 34a to 34d, 35a, 35b wiring.

Claims (5)

a mirror portion that reflects light;
a frame body provided to surround the mirror section and having a double structure of an inner frame body and an outer frame body ;
a pair of torsion bars having one end coupled to the mirror and the other end coupled to the frame on a first axis passing through the center of the mirror;
a support that supports the frame;
a first piezoelectric actuator that reciprocates the torsion bar about the first axis and at least a portion of which is coupled to the frame ;
a piezoelectric sensor that is provided in the frame and detects a voltage corresponding to the amount of deformation of the first piezoelectric actuator, the optical deflector comprising:
A first extending portion extending from the other end side of the torsion bar to the outer end of the frame along the first axis of the frame has a laminated structure in which thin films are laminated, Wiring connected to the piezoelectric sensor or the first piezoelectric actuator and extending to the support through the first extending portion, and a connection portion connecting the inner frame and the outer frame are provided. ,
The laminated structure includes an insulating film formed on one side of a substrate constituting the frame, an interlayer film formed on the upper surface of the insulating film, an electrode film formed on the upper surface of the interlayer film, and the electrode film. having an outer layer membrane to cover,
The optical deflector, wherein the wiring is formed so that the outer layer film does not come into contact with the substrate at least at the connecting portion . The optical deflector according to claim 1 ,
The optical deflector, wherein the wiring extending from the first extending portion in a direction along the shape of the outer frame is formed so that the outer layer film does not come into contact with the substrate . 3. The optical deflector according to claim 1, wherein
a second piezoelectric actuator for reciprocatingly rotating the mirror section around a second axis passing through the center of the mirror section and perpendicular to the first axis on the same plane;
In the second piezoelectric actuator, a plurality of piezoelectric cantilevers are arranged side by side on the second axis so that the longitudinal directions of the piezoelectric cantilevers are adjacent to each other, and one end is mechanically connected to the adjacent piezoelectric cantilevers so as to be folded back. An optical deflector characterized by: a mirror portion that reflects light;
a frame body provided to surround the mirror section and having a double structure of an inner frame body and an outer frame body ;
a pair of torsion bars having one end coupled to the mirror and the other end coupled to the frame on a first axis passing through the center of the mirror;
a first piezoelectric actuator that reciprocates the torsion bar about the first axis and at least a portion of which is coupled to the frame;
a second piezoelectric actuator for reciprocatingly rotating the mirror section around a second axis passing through the center of the mirror section and perpendicular to the first axis on the same plane;
a piezoelectric sensor that detects a voltage corresponding to the amount of deformation of the first piezoelectric actuator ,
In the second piezoelectric actuator, a plurality of piezoelectric cantilevers are arranged side by side on the second axis so that the longitudinal directions of the piezoelectric cantilevers are adjacent to each other, and one end is mechanically connected to the adjacent piezoelectric cantilevers so as to be folded back. an optical deflector comprising:
A second extending portion extending from the outer end of the inner frame along the second axis of the frame to the piezoelectric cantilever closest to the frame constituting the second piezoelectric actuator includes a laminated thin film. having a wiring connected to the piezoelectric sensor, the first piezoelectric actuator, or the second actuator,
When the second extending portion does not have the piezoelectric film and the electrode film of the piezoelectric film, and only the wiring exists, the laminated structure includes an insulating film formed on one side of the substrate constituting the frame, the an interlayer film formed on the upper surface of an insulating film, an electrode film formed on the upper surface of the interlayer film, and an outer layer film covering the electrode film;
The optical deflector, wherein the wiring in the second extending portion is formed so that the outer layer film does not come into contact with the substrate . a mirror portion that reflects light;
a frame provided to surround the mirror;
a pair of torsion bars having one end coupled to the mirror and the other end coupled to the frame on a first axis passing through the center of the mirror;
a first piezoelectric actuator that reciprocates the torsion bar about the first axis and at least a portion of which is coupled to the frame;
a second piezoelectric actuator for reciprocatingly rotating the mirror section around a second axis passing through the center of the mirror section and perpendicular to the first axis on the same plane;
a piezoelectric sensor that detects a voltage corresponding to the amount of deformation of the first piezoelectric actuator ,
In the second piezoelectric actuator, a plurality of piezoelectric cantilevers are arranged side by side on the second axis so that the longitudinal directions of the piezoelectric cantilevers are adjacent to each other, and one end is mechanically connected to the adjacent piezoelectric cantilevers so as to be folded back. an optical deflector comprising:
further comprising a wiring configured with a laminated structure in which thin films are laminated and connected to the piezoelectric sensor, the first piezoelectric actuator or the second actuator,
When the piezoelectric film and the electrode film of the piezoelectric film do not exist in the folded portion of the piezoelectric cantilever and only the wiring exists, the laminated structure is an insulating film formed on one side of the substrate constituting the folded portion of the piezoelectric cantilever. an interlayer film formed on the upper surface of the insulating film, an electrode film formed on the upper surface of the interlayer film, and an outer layer film covering the electrode film;
An optical deflector, wherein the wiring is formed so that the outer layer film does not come into contact with the substrate at the folded portion of the piezoelectric cantilever.

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