JP2020020916A - Optical scanning element - Google Patents

Abstract

To provide an optical scanning element which can simplify the manufacturing process.SOLUTION: An optical scanning element 1A includes: a reflection unit 11 in the shape of a flat plate for reflecting a light; a rocking shaft 12 for rocking the reflection unit 11; a mirror 3 on the rocking shaft 12 of the reflection unit 11, the mirror having a beam part 13 swingably supporting the reflection unit 11 to a seating 8; and a deflection angle detector 5 for detecting a deflection angle in the rocking direction of the mirror 3, the deflection angle detector 5 detecting, as the deflection angle of the mirror 3, a change in a magnetic flux caused by mirror rocking operations by a mirror driving unit 7, including driving and rocking the mirror 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical scanning device.

  The optical scanning element performs optical scanning by reflecting light such as laser light on a swinging mirror. The optical scanning element is used in various devices such as a laser projector and a head-up display (HUD). As the optical scanning element, for example, there is a MEMS mirror using a micro electro mechanical system (MEMS) technology.

  For example, a MEMS mirror is configured by processing a silicon wafer, placing a coil in a portion having elasticity, applying a magnetic force from the outside to a movable portion, forming a reflective surface on the movable portion and reflecting a laser beam. It scans by deflecting light. For example, in Patent Literature 1, a frame portion that can swing around the X axis, a shaft portion that supports the frame portion so as to swing around the X axis, and a shaft portion that is formed thicker than the thickness of the shaft portion. There is disclosed an optical scanner including a support portion for supporting the magnetic field, a coil provided on the frame portion, a permanent magnet for generating a magnetic field acting on the coil, and a soft magnetic material provided on the support portion.

JP 2014-56211 A

  However, the conventional MEMS mirror detects the deflection angle of the movable part by disposing a coil on a silicon wafer or forming a piezoresistive element, but requires a complicated manufacturing process and has room for improvement. .

  An object of the present invention is to provide an optical scanning element capable of simplifying a manufacturing process.

  In order to achieve the above object, an optical scanning device according to the present invention includes a flat reflecting portion for reflecting light, a first swing axis for swinging the reflecting portion, and a first swinging motion of the reflecting portion. A mirror provided on a shaft and having a pair of first beams for swingably supporting the reflecting portion with respect to a base, a mirror driving unit for swinging the mirror, and a swinging direction of the mirror A first deflection angle detection unit for detecting a deflection angle of the mirror, wherein the first deflection angle detection unit detects a magnetic flux caused by a mirror swing operation from the driving of the mirror driving unit to the swing of the mirror. The change is detected as a deflection angle of the mirror.

  Further, in the optical scanning element, in the mirror, at least the first beam portion is made of a magnetic material whose magnetic flux changes when distortion occurs, and the first deflection angle detection unit includes at least a swing of the reflection unit. It is preferable to detect a change in the magnetic flux of the first beam portion caused by the deviation as a deflection angle of the mirror.

  Further, in the optical scanning element, at least one of the mirror driving units is disposed at a position on the pedestal different from the first oscillating axis, and oscillates by applying a magnetic force to the reflecting unit. Is preferred.

  Further, in the above-mentioned optical scanning element, it is preferable that the mirror driving section is disposed at a position on a diagonal line of the mirror and opposed to the first swing axis.

  In the optical scanning device, the first deflection angle detection unit includes a winding coil, and a center axis of the winding coil and a first swing axis corresponding to the first beam overlap. It is preferable to be arranged at a position or a parallel position.

  Further, in the optical scanning element, a flat frame portion formed in a frame shape and having the mirror connected to the inside through the first beam portion, wherein the flat frame portion is orthogonal to the first swing axis in plan view. A frame provided with a second swinging shaft to be driven and a pair of second beam portions provided on the second swinging shaft of the frame portion and swingably supporting the frame portion with respect to the base. A second deflection angle detection unit that detects a deflection angle of the frame in a swing direction, wherein the second deflection angle detection unit includes a frame from when the mirror driving unit is driven until the frame swings. A change in magnetic flux caused by the swinging operation is detected as a deflection angle of the frame. In the frame, at least the second beam portion is made of a magnetic material that changes a magnetic flux when distortion occurs, and the second deflection angle is changed. The detection unit is configured to include a winding coil, The center axis of the winding coil and a second swing axis corresponding to the second beam portion are also arranged at overlapping positions, and the change in the magnetic flux of the second beam portion caused by the swing of the frame portion is suppressed. It is preferable to detect it as the deflection angle of the frame.

  ADVANTAGE OF THE INVENTION According to the optical scanning element which concerns on this invention, there exists an effect that a manufacturing process can be simplified.

FIG. 1 is a plan view showing a schematic configuration of the optical scanning element according to the first embodiment. FIG. 2 is a longitudinal sectional view illustrating a schematic configuration of the optical scanning element according to the first embodiment. FIG. 3 is a schematic diagram illustrating the swinging operation of the mirror according to the first embodiment. FIG. 4 is a schematic diagram for explaining the deflection angle detection of the mirror according to the first embodiment. FIG. 5 is a plan view illustrating a schematic configuration of the optical scanning element according to the first modification of the first embodiment. FIG. 6 is a plan view illustrating a schematic configuration of an optical scanning element according to Modification 2 of the first embodiment. FIG. 7 is a plan view illustrating a schematic configuration of the optical scanning element according to the second embodiment. FIG. 8 is a longitudinal sectional view illustrating a schematic configuration of the optical scanning element according to the second embodiment. FIGS. 9A and 9B are diagrams illustrating the relationship between the low-frequency current flow waveform of the optical scanning element according to the second embodiment and the deflection angle of the mirror. FIGS. 10A and 10B are diagrams showing the relationship between the high-frequency current flow of the optical scanning element according to the second embodiment and the deflection angle of the mirror. FIG. 11 is a schematic diagram illustrating the detection of the deflection angle of the mirror according to the second embodiment. FIG. 12 is a plan view illustrating a schematic configuration of an optical scanning element according to Modification Example 1 of the second embodiment. FIG. 13 is a plan view illustrating a schematic configuration of an optical scanning element according to Modification 2 of the second embodiment. FIG. 14 is a perspective view illustrating an arrangement example of a first deflection angle detection unit according to the second embodiment.

  Hereinafter, an optical scanning device according to an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited by the embodiments described below. The components in the following embodiments include those that can be easily replaced by those skilled in the art, or those that are substantially the same.

[First Embodiment]
FIG. 1 is a plan view showing a schematic configuration of the optical scanning element according to the first embodiment. FIG. 2 is a longitudinal sectional view illustrating a schematic configuration of the optical scanning element according to the first embodiment. FIG. 3 is a schematic diagram illustrating the swinging operation of the mirror according to the first embodiment. FIG. 4 is a schematic diagram for explaining the deflection angle detection of the mirror according to the first embodiment. FIG. 5 is a plan view illustrating a schematic configuration of the optical scanning element according to the first modification of the first embodiment. FIG. 6 is a plan view illustrating a schematic configuration of an optical scanning element according to Modification 2 of the first embodiment. FIG. 2 is a sectional view taken along the line AA in FIG.

  In the following description, the illustrated X direction indicates the width direction when the optical scanning element is viewed in plan, and the Y direction indicates the depth direction that is orthogonal to the X direction. The illustrated Z direction indicates a vertical direction orthogonal to the X direction and the Y direction.

  The optical scanning element 1A according to the first embodiment is a so-called one-axis type MEMS mirror, as shown in FIGS. The optical scanning element 1A is used for, for example, a laser projector, a head-up display, and the like. The optical scanning element 1A projects an image on a screen by reflecting a laser beam emitted from a light source (not shown) toward a screen (not shown) while the mirror 3 swings around the swing axis 12. I do. The optical scanning element 1A includes a body 2, a mirror 3, a body support 4, a pedestal 8, a deflection angle detector 5, a deflection angle detector support 6, and a mirror driver 7. You.

  The body 2 is a main body of a MEMS mirror formed in a flat shape. The body 2 is made of a magnetic material and a silicon wafer. This magnetic material is a magnetostrictive material, and includes, for example, Ni, an Fe-Ni alloy, an Fe-Co alloy, and soft ferrite. The body 2 is, for example, a thin film of a magnetostrictive material formed on a silicon wafer. Magnetostrictive materials generally have the property of being elastically deformed by an external magnetic field. In addition, the magnetic material has a characteristic that a magnetic flux changes when a distortion occurs due to an external force. For example, when compressive stress is applied in the axial direction of a parallel beam made of a magnetostrictive material, the magnetization decreases, and the magnetic flux around the parallel beam decreases. The body 2 has outwardly projecting portions 2 a at both ends on the swing shaft 12. The body 2 has a pair of punched holes 14 formed around the mirror 3. The punched hole 14 is a hole penetrating the body 2 in the up-down direction, and is formed so as to form the mirror 3.

  The mirror 3 is a movable portion that is made elastic by punching a part of the flat body 2 and is a portion that reflects light such as a laser beam. The mirror 3 has a reflecting portion 11, a swing shaft 12, and a pair of beam portions 13. The reflection section 11 has a reflection surface 11a that reflects light. The swing shaft 12 is a first swing shaft. The swing shaft 12 is a shaft that swings the reflection unit 11, and extends in the depth direction. The beam portion 13 is a first beam portion, is provided on the swing shaft 12 of the reflection portion 11, and supports the reflection portion 11 so as to be able to swing with respect to the pedestal 8. Beam 13 connects body 2 and reflector 11. The beam 13 serves as a swing axis of the reflector 11 and also functions as a torsion spring for suppressing the swing of the reflector 11. The beam portion 13 is elastically deformed by the swing of the reflecting portion 11 around the swing axis 12, and the surrounding magnetic flux changes when strain is added.

  The body supports 4 support both ends of the body 2 in the width direction. Each of the body supporting columns 4 is formed of a rectangular column that is long in the depth direction, and is erected on the pedestal 8. The pedestal 8 has substantially the same rectangular shape as the body 2, and is placed in parallel with the reflector 11.

  The deflection angle detection unit 5 is a first deflection angle detection unit, and detects a deflection angle ± θ (hereinafter, simply referred to as “deflection angle θ”) in the swing direction of the mirror 3 as shown in FIG. It is. The deflection angle detection unit 5 is arranged, for example, at a position facing the depth direction with the body 2 interposed therebetween. In other words, the deflection angle detection unit 5 is disposed on the swing shaft 12 at a position facing the mirror 3. For example, in the mirror swinging operation from the driving of the mirror driving unit 7 to the swinging of the mirror 3, the swing angle detecting unit 5 detects the change in the magnetic flux of the beam 13 caused by the swinging of the reflecting unit 11. Is detected as the deflection angle θ. The deflection angle detector 5 includes a winding coil 5a and an iron core 5b. The winding coil 5a is a copper wire wound around an iron core 5b. The iron core 5b is a steel material that is inserted into the inside of the winding coil 5a and used as a magnetic circuit. The deflection angle detection unit 5 of the present embodiment is arranged so that the center axis of the winding coil 5a and the swing shaft 12 corresponding to the beam 13 overlap.

  The support columns 6 for the deflection angle detection unit each support the deflection angle detection unit 5. Each of the deflection angle detection portion columns 6 is formed of a rectangular column that is long in the width direction. It is preferable that the swing angle detection unit support column 6 be erected on the pedestal 8, for example, but it is not limited to this.

  The mirror driving unit 7 applies a magnetic force to the reflection unit 11 to swing, and is configured by, for example, an electromagnet or the like. The mirror driving unit 7 according to the present embodiment is arranged at a position where the mirror unit 7 swings by applying a magnetic force to the reflecting unit 11. The mirror driving unit 7 is arranged at a position different from the position on the swing shaft 12, for example, as shown in FIG. The mirror driving unit 7 is disposed, for example, on a diagonal line of the rectangular mirror 3 and at a position opposite to the swing shaft 12.

  Next, the operation of the optical scanning element 1A according to the present embodiment will be described with reference to FIG. In the optical scanning element 1A according to the present embodiment, the mirror 3 including the magnetostrictive material swings around the swing axis 12 by the magnetic force of the mirror driving unit 7 which is an electromagnet, thereby polarizing the reflected light. For example, when the mirror 3 is swung by controlling the current supplied to two mirror driving units 7a and 7b located at positions opposing each other with the swing shaft 12 interposed therebetween, the mirror driving unit 7a shown in FIG. Is excited, a magnetic flux 30 is generated around the mirror driving unit 7a. When a magnetic force is applied to the reflector 11 by the magnetic flux 30, one of the widths of the reflector 11 is attracted to the mirror driving unit 7a side, and the reflector 11 tilts to the right around the swing shaft 12. At this time, a reaction force is applied to the mirror 3 to return to the original state in response to the torsion of the beam 13 in the swing direction, and the reflecting section 11 tends to tilt leftward about the swing axis 12. Further, when a current having a different direction from the current flowing to the mirror driving unit 7a is supplied to the mirror driving unit 7b, a magnetic flux 31 opposite to the magnetic flux 30 is generated around the mirror driving unit 7b. When a magnetic force is applied to the reflector 11 by the magnetic flux 31, the other in the width direction of the reflector 11 is attracted to the mirror driving unit 7 b side, and the reflector 11 tilts to the left around the swing shaft 12. In this way, for example, by controlling the energizing current to the two mirror driving units 7a and 7b located at opposing positions to alternately change the directions of the generated magnetic fluxes 30 and 31, the reflecting unit 11 can pivot the pivot shaft. 12 can be rocked in the rocking direction. In the optical scanning element 1A, the stress caused by the swing of the reflecting portion 11 acts on the body 2 via the beam portion 13, and the entire optical scanning element 1A may swing. It is preferable to be fixed to the pedestal 8 by the body support 4.

  Next, a shake angle detection operation of the shake angle detection unit 5 according to the present embodiment will be described with reference to FIG. In the optical scanning element 1A according to the present embodiment, the shake angle detector 5 detects the shake angle θ of the mirror 3 in the swing direction. When the mirror 3 swings in the swing direction, a distortion due to stress occurs at a connection portion between the beam portion 13 and the body 2. Since the body 2 connected to the beam portion 13 is made of a magnetostrictive material, the magnetization is reduced due to the generated strain, and the surrounding magnetic flux is reduced. When the magnetic flux around the beam portion 13 decreases, the magnetic flux around the winding coil 5a of the deflection angle detector 5 also decreases, and the exciting current flowing through the winding coil 5a decreases. In the deflection angle detection unit 5, for example, the winding coil 5a is connected to the deflection angle detection device 32. The deflection angle detection device 32 measures the excitation current flowing through the winding coil 5 a and detects a change in the excitation current as the deflection angle θ of the mirror 3. The shake angle detection device 32 has, for example, table information indicating the relationship between the change in the exciting current and the shake angle θ, and detects the shake angle θ of the mirror 3 based on the table information.

  As described above, the optical scanning element 1A according to the first embodiment is provided on the reflection unit 11 and the swing shaft 12 that swings the reflection unit 11, and the beam unit that supports the reflection unit 11 so as to swing. And a deflection angle detector 5 for detecting a deflection angle θ of the mirror 3 in the swing direction. In the mirror 3, at least the beam portion 13 is made of a magnetic material whose magnetic flux changes when distortion occurs. The deflection angle detector 5 detects a change in the magnetic flux of the beam 13 caused by the swing of the reflector 11 as the deflection angle θ of the mirror 3.

  According to the optical scanning device 1A having the above-described configuration, in the conventional MEMS mirror manufacturing process, a step of forming a piezoresistive element on a silicon wafer is not required in order to form a deflection angle sensor. The parts can be simplified, and the manufacturing cost can be reduced. Further, since the optical scanning element 1A detects a change in the magnetic flux of the beam portion 13 due to the swing of the reflecting portion 11 as the deflection angle θ of the mirror 3, it is possible to detect the deflection angle θ of the mirror 3 with a simple structure. Can be. Further, in the optical scanning element 1A, since the mirror 3 including the beam portion 13 is made of a magnetostrictive material and a silicon wafer, a magnetostrictive material having characteristics similar to silicon can be used, and characteristics such as piezoresistive elements are different. No material is required. Further, since the magnetostrictive material has metallic properties, at least the strength of the mirror 3 can be increased.

  In addition, at least one optical scanning element 1A according to the present embodiment is arranged at a position on the pedestal 8 different from the position on the oscillating shaft 12, and the mirror driving unit 7 that oscillates by applying a magnetic force to the reflecting unit 11. Is further provided. This eliminates the need for a step of arranging a coil on a silicon wafer in the conventional MEMS mirror manufacturing process, thereby simplifying a part of the manufacturing process and further reducing the manufacturing cost. In addition, since it is not necessary to dispose the coil on the silicon wafer, it is possible to swing the mirror 3 with a simple structure.

  Further, in the optical scanning element 1A according to the present embodiment, since at least one mirror driving unit 7 is disposed on the diagonal line of the mirror 3 and opposed to the mirror 3 with the swing shaft 12 interposed therebetween, the mirror 3 has a magnetic force. It is possible to swing easily.

  Further, in the optical scanning element 1A according to the present embodiment, the deflection angle detection unit 5 is configured to include the winding coil 5a, and the center axis of the winding coil 5a and the swing axis 12 corresponding to the beam 13 are formed. They are arranged at overlapping positions. This makes it possible to easily detect a change in the magnetic flux of the beam 13.

  In the optical scanning device 1A according to the first embodiment, the deflection angle detector 5 detects the change in the magnetic flux of the beam 13 caused by the swing of the reflector 11 in the mirror swing operation. Although detected as θ, it is not limited to this. For example, the deflection angle detector 5 may detect a change in magnetic flux generated by driving the mirror driver 7 as the deflection angle θ of the mirror 3 in the mirror swing operation. As described above, in the present embodiment, by controlling the current supplied to the two mirror driving units 7a and 7b to alternately change the directions of the magnetic fluxes 30 and 31 to be generated, the reflecting unit 11 is pivotally moved. It is swung about 12 in the swing direction. Therefore, the deflection angle detection unit 5 detects a change in magnetic flux generated by driving the mirror driving units 7a and 7b in the mirror swing operation as the deflection angle θ of the mirror 3. As described above, the deflection angle detection unit 5 detects a change in the magnetic flux generated by driving the mirror driving unit 7 as the deflection angle θ of the mirror 3 in the mirror swinging operation, so that the deflection angle θ of the mirror 3 has a simple structure. Can be detected. As a result, the optical scanning element 1A can simplify a part of the manufacturing process and reduce the manufacturing cost.

  In the optical scanning device 1A according to the first embodiment, the deflection angle detection unit 5 detects a change in magnetic flux generated by driving the mirror driving unit 7 as the deflection angle θ of the mirror 3 via the body 2. It may be. As described above, since the body 2 is made of a magnetic material, a change in magnetic flux of a magnetic field generated by driving the mirror driving unit 7 can be transmitted to the deflection angle detection unit 5. That is, the deflection angle detection unit 5 determines the change in the magnetic flux generated by the driving of the mirror driving unit 7 and transmitted through the body 2 made of the magnetostrictive material in the mirror swinging operation, based on the deflection angle θ of the mirror 3. Detected as Thus, the deflection angle θ of the mirror 3 can be detected with a simple structure. As a result, the optical scanning element 1A does not require a step for forming the deflection angle sensor, and can simplify a part of the manufacturing process and reduce the manufacturing cost.

[Modifications 1 and 2 of First Embodiment]
Next, optical scanning elements 1B and 1C according to modified examples 1 and 2 of the first embodiment will be described with reference to FIGS. In the optical scanning element 1A according to the first embodiment, the mirror driving unit 7 is arranged at the position shown in FIG. 1. However, if the mirror driving unit 7 can be swung by applying a magnetic force to the mirror 3, for example, FIG. 5 and the position shown in FIG. In the optical scanning device 1B shown in FIG. 5, the mirror driving unit 7 is arranged at a position different from the position on the swing shaft 12 and on a diagonal line of the rectangular mirror 3. In the optical scanning element 1C shown in FIG. 6, the mirror driving unit 7 is disposed at a position different from the position on the oscillation axis 12 and at both ends in the direction orthogonal to the oscillation axis 12 of the mirror 3. Note that the mirror driving unit 7 may be disposed at all positions shown in the drawing, or may be disposed only at any one position.

[Second embodiment]
Next, an optical scanning element according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a plan view illustrating a schematic configuration of the optical scanning element according to the second embodiment. FIG. 8 is a longitudinal sectional view illustrating a schematic configuration of the optical scanning element according to the second embodiment. FIGS. 9A and 9B are diagrams illustrating the relationship between the low-frequency current flow waveform of the optical scanning element according to the second embodiment and the deflection angle of the mirror. FIGS. 10A and 10B are diagrams showing the relationship between the high-frequency current flow of the optical scanning element according to the second embodiment and the deflection angle of the mirror. FIG. 11 is a schematic diagram illustrating the detection of the deflection angle of the mirror according to the second embodiment. FIG. 12 is a plan view illustrating a schematic configuration of an optical scanning element according to Modification Example 1 of the second embodiment. FIG. 13 is a plan view illustrating a schematic configuration of an optical scanning element according to Modification 2 of the second embodiment. FIG. 14 is a perspective view illustrating an arrangement example of a deflection angle detection unit according to the second embodiment. FIG. 8 is a sectional view taken along the line BB in FIG.

  The optical scanning element 1D according to the second embodiment is a so-called two-axis type MEMS mirror, as shown in FIGS. The optical scanning element 1D is different from the optical scanning element 1A according to the first embodiment in that the optical scanning element 1D includes a frame 9 and a deflection angle detection unit 25. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted or simplified.

  The frame 9 has a flat frame portion 21, a swing shaft 22, and a pair of beam portions 23. The frame 21 has a mirror 3 formed in a frame shape and connected to the inside through the beam 13. The swing shaft 22 is a second swing shaft. The swing shaft 22 swings the frame 9 and is orthogonal to the swing shaft 12 in a plan view. The swing shaft 12 of the present embodiment is a first swing shaft and extends in the width direction. The beam portion 23 is a second beam portion, is provided on the swing shaft 22 of the frame portion 21, and supports the frame portion 21 to be able to swing with respect to the pedestal 8. Beam 23 connects body 2 and frame 9. The body 2 has a pair of punched holes 24 formed around the frame 9. The punching hole 24 is a hole penetrating in the vertical direction of the body 2 and is formed so as to form the frame 9. The beam portion 13 of the present embodiment is a first beam portion, and connects the frame 9 and the reflection portion 11. The beam 23 serves as a swing axis of the frame 9 and also functions as a torsion spring for suppressing the swing of the frame 9. The beam portion 23 is elastically deformed by the swing of the frame 9 around the swing shaft 22, and when a strain is added, the surrounding magnetic flux changes.

  The deflection angle detection unit 25 is a second deflection angle detection unit that detects the deflection angle θ of the frame 9 in the swing direction. The swing angle detection unit 25 of the present embodiment can detect the swing angle θ of the mirror 3 included in the frame 9 in the swing direction. The deflection direction of the mirror 3 detected by the deflection angle detection unit 25 is orthogonal to the deflection direction of the mirror 3 detected by the deflection angle detection unit 5. The deflection direction of the mirror 3 detected by the deflection angle detection unit 25 is, for example, the width direction and the sub-scanning direction. On the other hand, the deflection direction of the mirror 3 detected by the deflection angle detection unit 5 is, for example, the depth direction and the main scanning direction. The deflection angle detection unit 25 is disposed at a position facing the depth direction with the body 2 interposed therebetween. The deflection angle detection unit 25 is disposed on the swing shaft 22 at a position facing the mirror 3 with the mirror 3 interposed therebetween. For example, in the frame swinging operation from the driving of the mirror driving unit 7 to the swinging of the frame 9, the swing angle detecting unit 25 detects the change of the magnetic flux of the beam 23 due to the swinging of the frame 21. Is detected as the deflection angle θ. The deflection angle detection unit 25 includes a winding coil 5a and an iron core 5b, like the deflection angle detection unit 5. The deflection angle detection unit 25 of the present embodiment is disposed at a position where the center axis of the winding coil 5a and the swing shaft 22 corresponding to the beam 23 overlap.

  The deflection angle detector 5 of the present embodiment is a first deflection angle detector, and detects the deflection angle θ of the mirror 3 in the swing direction. The deflection angle detector 5 is arranged at a position where the center axis of the winding coil 5a and the swing axis 12 corresponding to the beam 13 are parallel. The deflection angle detection unit 5 is disposed, for example, at a position on a diagonal line of the mirror 3 and facing the swing shaft 12 therebetween. The deflection angle detection unit 5 detects, as the deflection angle θ of the mirror 3, a change in the magnetic flux of the beam 13 caused by the swing of the reflection unit 11 in the above-described mirror swing operation.

  The mirror driving unit 7 of the present embodiment is preferably disposed at a position where the mirror unit 7 applies a magnetic force to each of the reflection unit 11 and the frame 9 to swing the mirror unit. For example, as shown in FIG. Placed in the position. The mirror drive unit 7 is disposed, for example, on a diagonal line of the rectangular frame 9 and opposed to each other with the swing shaft 22 interposed therebetween.

  Next, the operation of the optical scanning element 1D according to the present embodiment will be described with reference to FIGS. 1, 9A, 9B, 10A, and 10B. In the optical scanning element 1D according to the present embodiment, the mirror 3 oscillates around two orthogonal oscillation axes 12 and 22 by the magnetic force of the mirror driving unit 7, thereby polarizing the reflected light. . For example, a case will be described in which the mirror 3 is swung by controlling the current supplied to two mirror driving units 7a and 7b located on the diagonal line of the mirror 3 and opposed to each other with the swing shaft 22 interposed therebetween. A current I in which a high-frequency component and a low-frequency component are superimposed flows through the mirror driving units 7a and 7b as in a general MEMS mirror. When the current I flows through the mirror driving units 7a and 7b (FIGS. 9A and 10A), the frame 9 swings around the swing shaft 22 in the width direction (X direction) due to the low frequency component. (FIG. 9B). On the other hand, since the high-frequency component of the current I is small, there is no effect on the frame 9 (FIG. 10B). The mirror 3 swings in the depth direction (Y direction) around the swing shaft 12 by a high-frequency component (for example, the resonance frequency f) (FIG. 10B). When the high-frequency component of the current I is set in accordance with the resonance frequency f of the mirror 3 as described above, the driving force of the mirror driving units 7a and 7b is small (FIG. 10A) and deviates from the resonance frequency of the frame 9. Therefore, the influence can be ignored. On the other hand, since the high-frequency component of the current I matches the resonance frequency f of the mirror 3, the mirror 3 can swing with a large deflection angle. For example, in a MEMS mirror for a laser projector, the resonance frequency of the frame 9 about the oscillation axis 22 is 1 KHz or less, and the resonance frequency of the mirror 3 about the oscillation axis 12 is 20 KHz or more.

  Next, a shake angle detection operation of the shake angle detection unit 5 according to the present embodiment will be described with reference to FIG. In the optical scanning element 1D according to the present embodiment, the shake angle detector 5 detects the shake angle θ of the mirror 3 in the swing direction. When the mirror 3 swings in the swinging direction, distortion occurs due to stress at a connection portion between the beam portion 13 and the frame 9. Since the frame 9 connected to the beam portion 13 is made of a magnetostrictive material, similarly to the body 2, the generated strain reduces the magnetization and the surrounding magnetic flux. When the magnetic flux around the beam portion 13 decreases, the magnetic flux around the winding coil 5a of the deflection angle detector 5 also decreases, and the exciting current flowing through the winding coil 5a decreases. In the deflection angle detection unit 5, for example, the winding coil 5a is connected to the deflection angle detection device 32. The deflection angle detection device 32 measures the excitation current flowing through the winding coil 5 a and detects a change in the excitation current as the deflection angle θ of the mirror 3. The shake angle detection device 32 has, for example, table information indicating the relationship between the change in the exciting current and the shake angle θ, and detects the shake angle θ of the mirror 3 based on the table information.

  In the deflection angle detection unit 25 according to the present embodiment, when the frame 9 swings in the swing direction, a strain occurs due to stress in a connection portion between the beam 23 and the body 2. Since the body 2 connected to the beam portion 23 is made of a magnetostrictive material, the generated strain reduces the magnetization and the surrounding magnetic flux. When the magnetic flux around the beam portion 23 decreases, the magnetic flux around the winding coil 5a of the deflection angle detector 25 also decreases, and the exciting current flowing through the winding coil 5a decreases. In the deflection angle detection unit 25, the winding coil 5 a is connected to a deflection angle detection device 32, and the deflection angle detection device 32 detects the deflection angle θ of the frame 9.

  As described above, the optical scanning device 1D according to the second embodiment is a flat plate having the mirror 3 formed in a frame shape and connected to the optical scanning device 1A via the beam 13 inside. A frame 21, a swing shaft 22 orthogonal to the swing shaft 12 in a plan view, and a pair provided on the swing shaft 22 of the frame 21 and supporting the frame 21 to be able to swing with respect to the base 8. And a deflection angle detection unit 25 that detects a deflection angle θ of the frame 9 in the swing direction. In the frame 9, at least the beam portion 23 is made of a magnetic material. The deflection angle detector 25 detects a change in the magnetic flux of the beam portion 23 caused by the swing of the frame portion 21 as the deflection angle θ of the frame 9.

  According to the optical scanning element 1D having the above configuration, the same effects as those of the optical scanning element 1A according to the first embodiment can be obtained.

  Further, in the optical scanning element 1D according to the present embodiment, the deflection angle detection unit 25 is configured to include the winding coil 5a, and the center axis of the winding coil 5a and the swing shaft 22 corresponding to the beam 23 are formed. They are arranged at overlapping positions. This makes it possible to easily detect a change in the magnetic flux of the beam 23.

  In the optical scanning element 1D according to the present embodiment, the deflection angle detector 5 is disposed at a position where the center axis of the winding coil 5a and the swing axis 12 corresponding to the beam 13 are parallel. This makes it possible to detect a change in the magnetic flux of the beam 13 without interfering with the magnetic flux of the beam 23 detected by the deflection angle detecting unit 25.

  Further, in the optical scanning element 1D according to the present embodiment, at least one mirror driving unit 7 is disposed on a diagonal line of the mirror 3 and opposed to the mirror 3 with the swing shaft 12 interposed therebetween. It is possible to swing easily.

  In the optical scanning device 1D according to the second embodiment, in the swinging motion of the frame 9, the swing angle detecting unit 25 detects the change in the magnetic flux of the beam 23 caused by the swing of the frame 21. Although detected as θ, it is not limited to this. For example, the shake angle detection unit 25 may detect a change in magnetic flux generated by driving the mirror drive unit 7 as the shake angle θ of the frame 9 in the frame swing operation. As described above, in the present embodiment, the current flowing through the two mirror driving units 7a and 7b is controlled to alternately change the directions of the generated magnetic fluxes 30 and 31 so that the frame 9 is moved to the swing shaft 22. Swing in the swing direction around. Therefore, the deflection angle detection unit 25 detects a change in magnetic flux generated by driving the mirror driving units 7a and 7b in the frame swing operation as the deflection angle θ of the frame 9. As described above, the swing angle detecting section 25 detects the change in the magnetic flux generated by driving the mirror driving section 7 as the swing angle θ of the frame 9 in the frame swinging operation, so that the swing angle θ of the frame 9 has a simple structure. Can be detected. As a result, like the optical scanning element 1A, a part of the manufacturing process of the optical scanning element 1D can be simplified, and the manufacturing cost can be reduced.

  In the optical scanning element 1D according to the second embodiment, the deflection angle detection unit 25 detects a change in magnetic flux generated by driving the mirror driving unit 7 as the deflection angle θ of the frame 9 via the body 2. It may be. As described above, since the body 2 is made of a magnetostrictive material, a change in magnetic flux of a magnetic field generated by driving the mirror driving unit 7 can be transmitted to the deflection angle detection unit 25. That is, in the frame swinging operation, the deflection angle detection unit 25 detects the change in the magnetic flux generated by driving the mirror driving unit 7 and transmitted through the body 2 made of the magnetostrictive material, to the deflection angle θ of the frame 9. Detected as Thus, the deflection angle θ of the frame 9 can be detected with a simple structure. As a result, in the optical scanning element 1D, a step for forming the deflection angle sensor is not required, and a part of the manufacturing process can be simplified, and the manufacturing cost can be reduced.

[Modifications 1 and 2 of Second Embodiment]
Next, optical scanning elements 1E and 1F according to modified examples 1 and 2 of the second embodiment will be described with reference to FIGS. In the optical scanning element 1D according to the second embodiment, the mirror driving unit 7 is arranged at the position shown in FIG. 7. 12 and the position shown in FIG. In the optical scanning element 1E shown in FIG. 12 and the optical scanning element 1F shown in FIG. 13, the mirror driving unit 7 is arranged at a position different from the position on the swing shaft 22 and on the diagonal line of the rectangular frame 9. I have. The mirror driving units 7 shown in FIG. 12 are respectively arranged at diagonal portions of the frame 9. The mirror driving unit 7 illustrated in FIG. 13 is disposed at a position facing the deflection angle detection unit 5 with the swing shaft 22 interposed therebetween. Note that the mirror driving unit 7 may be disposed at all positions shown in the drawing, or may be disposed only at any one position.

  In addition, in the optical scanning element 1D according to the second embodiment, the deflection angle detection unit 5 is arranged at the position shown in FIGS. 7, 8, and 11 to 13, but is not limited thereto. Absent. That is, if the swing angle detection unit 5 is arranged at a position where the center axis of the winding coil 5a and the swing axis 12 corresponding to the beam unit 13 are parallel to each other, as shown in FIG. It may be arranged around. The deflection angle detection unit 5 may be arranged, for example, in the width direction (X direction) of the body 2 orthogonal to the swing shaft 22. Further, the deflection angle detection unit 5 may be arranged on the lower surface side of the body 2 connected to the body support 4, or may be arranged on the upper surface side opposite to the lower surface side. Further, the deflection angle detection unit 5 may be disposed in the punched hole 24 of the body 2 or may be disposed on the side of the protrusion 2a.

  In addition, in the said 1st Embodiment, although the deflection angle detection part 5 is arrange | positioned, it may be arrange | positioned at any one. Further, in the second embodiment, the two deflection angle detection units 5 and 25 are arranged, but one of them may be arranged on either one.

  In the first and second embodiments, the mirror driving unit 7 is disposed at a plurality of positions, but one mirror driving unit 7 may be disposed at any one position.

1A, 1B, 1C, 1D, 1E, 1F Optical Scanning Element 2 Body 2a Projection 3 Mirror 4 Body Support 5,25 Shake Angle Detector 5a Winding Coil 5b Iron Core 6 Shake Angle Support 7,7a, 7b Mirror drive unit 8 Base 9 Frame 11 Reflecting unit 11a Reflecting surface 12,22 Swing axis 13,23 Beam unit 14,24 Punch hole 21 Frame unit 30,31 Magnetic flux 32 Deflection angle detecting device

Claims (6)

A plate-like reflecting portion for reflecting light, a first swing axis for swinging the reflecting portion, and a first swinging axis of the reflecting portion, wherein the reflecting portion swings with respect to a base. A mirror having a pair of first beams for freely supporting;
A mirror driving unit for swinging the mirror,
A first deflection angle detection unit that detects a deflection angle of the mirror in the swing direction;
With
The first deflection angle detection unit includes:
The mirror drive unit detects a change in magnetic flux due to a mirror swing operation from driving to swinging the mirror as a swing angle of the mirror,
An optical scanning element characterized by the above-mentioned. The mirror is
At least the first beam portion is made of a magnetic material whose magnetic flux changes when strain occurs,
The first deflection angle detection unit includes:
Detecting at least a change in magnetic flux of the first beam portion caused by the swing of the reflection portion as a deflection angle of the mirror;
The optical scanning device according to claim 1. The mirror drive unit is arranged at least one of the pedestals at a position different from the position on the first swing axis, and applies a magnetic force to the reflection unit to swing the mirror.
The optical scanning element according to claim 1. The mirror driving unit,
Disposed on a diagonal line of the mirror and opposed to each other across the first swing axis;
The optical scanning device according to claim 3. The first deflection angle detection unit includes:
It is configured to include a winding coil,
It is arranged at a position where a central axis of the winding coil and a first swing axis corresponding to the first beam portion overlap or are parallel.
The optical scanning element according to claim 1. A plate-shaped frame portion having a frame shape and having the mirror connected to the inside through the first beam portion, a second swing axis orthogonal to the first swing axis in plan view, A frame provided on the second swinging shaft of the frame, and having a pair of second beams for swingably supporting the frame with respect to the pedestal;
A second deflection angle detection unit that detects a deflection angle of the frame in the swing direction;
Further comprising
The second deflection angle detection unit includes:
Detecting a change in magnetic flux due to a frame swing operation from the drive of the mirror driving unit to swing the frame as a deflection angle of the frame,
The frame is
At least the second beam portion is made of a magnetic material whose magnetic flux changes when strain occurs,
The second deflection angle detection unit includes:
It is configured to include a winding coil,
At least a center axis of the winding coil and a second swing axis corresponding to the second beam portion are arranged at positions overlapping each other;
Detecting a change in magnetic flux of the second beam portion due to the swing of the frame portion as a deflection angle of the frame;
The optical scanning device according to claim 1.

Images