Manufacturing method of actuator device

Abstract

The manufacturing method of the actuator device of the present invention includes, in sequence: a preparation step, preparing an actuator device comprising: a support portion, a movable portion, a connecting portion connecting the movable portion to the support portion in such a way that the movable portion can swing around a predetermined axis, and a metal member disposed in such a way that stress is applied when the movable portion swings around the axis; a swinging step, causing the movable portion to swing around the axis for a predetermined time; an acquisition step, acquiring parameters related to the viscous resistance of the vibration of the movable portion around the axis; and a determination step, in which the actuator device is determined to be qualified if the difference between the parameter acquired in the acquisition step and a reference value of the parameter corresponding to the start time of the swinging step is a predetermined value or more in the direction of decreasing viscous resistance, and the actuator device is determined to be unqualified if the difference is less than the predetermined value.

Description

Technical Field

[0001] One aspect of the present invention relates to a method for manufacturing an actuator device, for example, configured as a MEMS (Micro Electro Mechanical Systems) device. Background Technology

[0002] As such an actuator device, one known actuator device includes: a support portion, a movable portion oscillatingly connected to the support portion, and a coil that generates a driving force for oscillating the movable portion (see, for example, Patent Document 1). Patent Document 1 discloses a MEMS scanning mirror in which a reflector is provided on the movable portion.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-171226 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] In the aforementioned actuator devices, the vibration characteristics of the movable part sometimes change over time during use at the customer's site after leaving the factory. Such changes in vibration characteristics can cause malfunctions and therefore need to be suppressed.

[0008] Therefore, one aspect of the present invention is to provide a method for manufacturing an actuator device that can produce an actuator device with stable quality.

[0009] Technical solutions for solving the problem

[0010] A method for manufacturing an actuator device according to one aspect of the present invention includes, sequentially: a preparation step, preparing an actuator device, the actuator device comprising: a support portion, a movable portion, a connecting portion connecting the movable portion to the support portion in such a way that the movable portion can swing about a predetermined axis, and a metal member disposed in such a way that stress is applied when the movable portion swings about the axis; a swinging step, causing the movable portion to swing about the axis for a predetermined time; an acquisition step, acquiring parameters related to viscous resistance in the vibration of the movable portion about the axis; and a determination step, wherein if the difference between the parameter acquired in the acquisition step and a reference value of the parameter corresponding to the start time of the swinging step is a predetermined value or more in the direction of decreasing viscous resistance, the actuator device is determined to be qualified; and if the difference is less than the predetermined value, the actuator device is determined to be unqualified.

[0011] In the case where an actuator device includes a metal member configured to be stressed when a movable part swings about an axis, when the movable part swings about the axis, the metal member may repeatedly plastically deform due to the stress. When the metal member repeatedly plastically deforms, it may become difficult to generate plastic deformation due to the progress of work hardening. As a result, the viscous resistance of the vibration of the movable part about the axis gradually decreases. The inventors of the present invention have found that the decrease in this viscous resistance is one of the reasons for the change in the vibration characteristics of the movable part. Therefore, in the manufacturing method of this actuator device, after a swinging step of swinging the movable part about the axis for a predetermined time, an obtaining step of obtaining a value of a parameter related to the viscous resistance of the vibration of the movable part about the axis is performed. Furthermore, when the difference between the parameter obtained in the obtaining step and the reference value of the parameter corresponding to the start time point of the swinging step is a predetermined value or more in the direction of decreasing viscous resistance, the actuator device is determined to be qualified, and when the difference is less than the predetermined value, the actuator device is determined to be unqualified. For example, a qualified actuator device is shipped out, and an unqualified actuator device is not shipped out. By pre-reducing the viscous resistance by swinging the movable part for a predetermined time before shipping, the change in the vibration characteristics of the movable part at the customer can be suppressed, and thus the quality of the actuator device can be stabilized. In addition, in the actuator device, there may be a device in which the viscous resistance does not decrease even when the movable part is swung for a predetermined time. However, by determining an actuator device in which the difference between the obtained parameter and the reference value is a predetermined value or more to be qualified, only the actuator device with a reduced viscous resistance can be shipped out. As a result, the quality of the actuator device can be further stabilized. Therefore, according to the manufacturing method of this actuator device, an actuator device with stable quality can be obtained.

[0012] Alternatively, the parameter may be related to a Q value, a resonance frequency, a drive current value for obtaining a predetermined swing angle, or a swing angle when a predetermined drive current is applied. In this case, the change in the viscous resistance can be appropriately grasped.

[0013] Alternatively, in the swinging step, the movable part may be swung in a state where the temperatures of the movable part and the connecting part are higher than the temperature of the supporting part. In this case, the viscous resistance can be effectively reduced.

[0014] Alternatively, in the swinging step, the movable part may be swung at a certain temperature. In this case, for example, by performing the swinging step at the same temperature as the usage environment at the customer, the change in the vibration characteristics of the movable part at the customer can be reliably suppressed.

[0015] Alternatively, in the swinging step, the movable part may be swung under a certain pressure. In this case, the change in the viscous resistance caused by the change in the atmospheric pressure can be suppressed, and the change in the viscous resistance caused by the work hardening of the metal member can be appropriately grasped.

[0016] Alternatively, in the preparation process, multiple actuator devices are prepared, and for each of these actuator devices, a swinging process, an acquisition process, and a judgment process are performed. In this case, actuator devices with stable quality can be manufactured efficiently.

[0017] Alternatively, the actuator device prepared in the preparation process may include a coil that generates a driving force for oscillating the movable part, and the coil may be a metal component. In this case, the quality of the actuator device with the coil can be stabilized.

[0018] Alternatively, the coil can be embedded in a groove. In this case, the cross-sectional area of ​​the coil becomes larger, and the coil is prone to work hardening due to repeated plastic deformation. However, according to the manufacturing method of this actuator device, even in such a case, changes in the vibration characteristics of the movable part at the customer's location can be suppressed.

[0019] Alternatively, the actuator device prepared in the preparation process may include: a drive element that generates a driving force for oscillating the movable part, and wiring electrically connected to the drive element, the wiring constituting a metal component. In this case, the quality of the actuator device with wiring electrically connected to the drive element can be stabilized.

[0020] Alternatively, the wiring can be embedded in a groove. In this case, the cross-sectional area of ​​the coil becomes larger, and the coil is prone to work hardening due to repeated plastic deformation. However, according to the manufacturing method of this actuator device, even under such circumstances, changes in the vibration characteristics of the movable part at the customer's location can be suppressed.

[0021] Alternatively, the actuator device prepared in the preparation process may also include: an encapsulation that hermetically seals and houses the support, movable part, connecting part, and metal components. In this case, changes in viscous resistance caused by variations in atmospheric pressure can be suppressed, and changes in viscous resistance caused by work hardening of the metal components can be appropriately controlled.

[0022] Alternatively, in the actuator device prepared during the preparation process, the movable part includes a first movable part and a second movable part, and the connecting part includes a first connecting part that connects the first movable part and the second movable part in such a way that the first movable part can swing around a first axis; and a second connecting part that connects the second movable part to the support part in such a way that the second movable part can swing around a second axis. In the swinging process, the first movable part swings around the first axis and the second movable part swings around the second axis for a predetermined time. In this case, the swinging process can be performed under the same operating conditions as the customer's usage environment, and changes in the vibration characteristics of the movable part at the customer's location can be reliably suppressed. Furthermore, when the movable part swings around multiple axes, the drive current increases and the ambient temperature tends to rise, but according to the manufacturing method of this actuator device, even in this case, changes in the vibration characteristics of the movable part at the customer's location can be suppressed.

[0023] Alternatively, the movable part can be made to resonate during the oscillation process. In this case, the stress acting on the metal component increases, and the metal component is prone to work hardening due to repeated plastic deformation. However, according to the manufacturing method of this actuator device, even under such circumstances, changes in the vibration characteristics of the movable part at the customer's location can be suppressed.

[0024] The effects of the invention

[0025] According to one aspect of the present invention, a method for manufacturing an actuator device that can produce actuator devices with stable quality can be provided. Attached Figure Description

[0026] Figure 1 This is a top view of the actuator device in the embodiment.

[0027] Figure 2 It is a cross-sectional view of the coil's perimeter.

[0028] Figure 3 This is a flowchart used to illustrate the manufacturing method of actuator devices.

[0029] Figure 4 This is a cross-sectional view used to illustrate the oscillation process.

[0030] Figure 5 This is a top view used to illustrate an example of temperature distribution in a swinging process.

[0031] Figure 6 This is a graph illustrating an example of the relationship between the operating time and the rate of change of the drive current value.

[0032] Figure 7 It is a diagram showing the vibration model of the actuator device.

[0033] Figure 8 This is a chart used to illustrate the calculation method of Q value using the half-value width method. Detailed Implementation

[0034] In the following detailed description, one embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same or equivalent elements will be referred to by the same reference numerals, and repeated descriptions will be omitted.

[0035] [Actuator Devices]

[0036] like Figure 1 As shown, the actuator device 1 includes: a support portion 2, a first movable portion 3, a second movable portion 4, a pair of first connecting portions 5 and 6, a pair of second connecting portions 7 and 8, and a magnetic field generating portion M. The support portion 2, the first movable portion 3, the second movable portion 4, the pair of first connecting portions 5 and 6, and the pair of second connecting portions 7 and 8 are integrally formed, for example, from an SOI (Silicon on Insulator) substrate. That is, the actuator device 1 is configured as a MEMS device. The SOI substrate has a pair of silicon layers and an insulating layer disposed between the pair of silicon layers. The support portion 2 is composed of a pair of silicon layers and an insulating layer. The first movable portion 3, the second movable portion 4, the pair of first connecting portions 5 and 6, and the pair of second connecting portions 7 and 8 are composed of one of the pair of silicon layers.

[0037] In actuator device 1, the first movable part 3, which has a reflective mirror surface 10, is oscillating about the X-axis (first axis) and Y-axis (second axis perpendicular to the first axis), which are orthogonal to each other. That is, actuator device 1 is configured as a reflective mirror device. Actuator device 1 can be used in optical communication optical switches, optical scanners, etc.

[0038] The support portion 2 is formed into a frame with a rectangular shape, supporting the first movable portion 3 and the second movable portion 4, etc. The first movable portion 3 is disposed inside the support portion 2. The first movable portion 3 has a main body portion 3a, an annular portion 3b, and a pair of connecting portions 3c.

[0039] The main body 3a is formed in a circular shape. A circular reflective mirror 10 is provided on the surface of the main body 3a, for example, by means of a metal film made of aluminum. The annular portion 3b is formed in a ring shape to surround the main body 3a. A pair of connecting portions 3c are disposed on both sides of the main body 3a on the Y-axis, connecting the main body 3a and the annular portion 3b.

[0040] The second movable part 4 is frame-shaped and is arranged inside the support part 2 to surround the first movable part 3. The magnetic field generating part M is constructed, for example, using a permanent magnet employing a Halbach array, and generates a magnetic field that acts on the coils 14 and 15 described later. The magnetic field generating part M is arranged on one side perpendicular to the X-axis and Y-axis (opposite to the reflecting mirror 10) relative to the support part 2, the first movable part 3, and the second movable part 4.

[0041] First connecting parts 5 and 6 are disposed on both sides of the first movable part 3 on the X-axis. The first connecting parts 5 and 6 connect the first movable part 3 (annular part 3b) to the second movable part 4 on the X-axis such that the first movable part 3 can swing around the X-axis (with the X-axis as the center line). The first connecting parts 5 and 6, as described later, are connected to the support part 2 via the second movable part 4 and the second connecting parts 7 and 8. That is, the first connecting parts 5 and 6 can also be considered as connecting the first movable part 3 to the support part 2 such that the first movable part 3 can swing around the X-axis. Each first connecting part 5 and 6 is a torsion bar that deforms to the twist when the first movable part 3 swings around the X-axis. Each first connecting part 5 and 6 extends linearly on the X-axis.

[0042] The second connecting parts 7 and 8 are disposed on both sides of the second movable part 4 on the Y-axis. The second connecting parts 7 and 8 connect the second movable part 4 to the support part 2 on the Y-axis such that the second movable part 4 can swing about the Y-axis (with the Y-axis as the center line). Each of the second connecting parts 7 and 8 is a torsion bar that deforms to the twist when the second movable part 4 swings about the Y-axis. Each of the second connecting parts 7 and 8 extends in a meandering manner.

[0043] like Figure 1 and Figure 2 As shown, the actuator device 1 also includes a pair of coils (driving elements) 14 and 15, a first wiring 21, a second wiring 22, a third wiring 23, a fourth wiring 24, and external terminals 25, 26, 27, and 28. Each coil 14 and 15 is disposed on the second movable portion 4 in a manner that surrounds the first movable portion 3. Each coil 14 and 15 is wound multiple times around the first movable portion 3 to form a spiral shape. The pair of coils 14 and 15 are arranged in a staggered manner along the width direction of the second movable portion 4.

[0044] exist Figure 1 In the diagram, the configuration area R containing coils 14 and 15 is shown by a cross-sectional line. For example... Figure 2As shown, the second movable part 4 is provided with a slot 31 having a shape corresponding to each coil 14, 15. An insulating layer 32 is provided on the inner surface of the slot 31, and an insulating layer 33 is provided on the insulating layer 32. Each coil 14, 15 is arranged in the slot 31 via the insulating layers 32, 33. That is, each coil 14, 15 is configured as an embedded wiring within the slot 31. Each coil 14, 15 is made of a metal material such as copper or gold.

[0045] Insulating layer 34 is configured to cover coils 14 and 15 and insulating layer 33. Insulating layer 35 is provided on insulating layer 34. Each insulating layer 32 to 35 is made of, for example, silicon oxide, silicon nitride, silicon oxynitride, etc. Each insulating layer 32 to 35 is integrally formed to cover the surfaces of support portion 2, first movable portion 3, second movable portion 4, first connecting portions 5 and 6, and second connecting portions 7 and 8.

[0046] External terminals 25-28 are electrode pads provided on the support portion 2 and are electrically connected to control devices, etc., disposed outside the actuator device 1. First wiring 21 is electrically connected to the inner end of coil 14 and external terminal 25. First wiring 21 extends from the inner end of coil 14 to external terminal 25 via second connecting portion 7. Second wiring 22 is electrically connected to the outer end of coil 14 and external terminal 26. Second wiring 22 extends from the outer end of coil 14 to external terminal 26 via second connecting portion 8.

[0047] The third wiring 23 is electrically connected to the inner end of the coil 15 and the outer terminal 27. The third wiring 23 extends from the inner end of the coil 15 to the outer terminal 27 via the second connecting portion 7. The fourth wiring 24 is electrically connected to the outer end of the coil 15 and the outer terminal 28. The fourth wiring 24 extends from the outer end of the coil 15 to the outer terminal 28 via the second connecting portion 8. Like the coils 14 and 15, each of the wirings 21 to 24 is disposed within the groove 31 through insulating layers 32 and 33, forming an embedded wiring configuration within the groove 31. Each of the wirings 21 to 24 is made of, for example, a metallic material such as aluminum. Compared to copper, aluminum has a lower yield stress and is more easily plastically deformed.

[0048] In the actuator device 1 configured as described above, when a linearly operating drive current is applied to the coil 14 via external terminals 25 and 26 and wiring 21 and 22, a Lorentz force (driving force) acts on the coil 14 through interaction with the magnetic field generated by the magnetic field generating part M. By utilizing the balance between this Lorentz force and the elastic force of the second connecting parts 7 and 8, the second movable part 4 can be made to swing around the Y-axis (linear operation). At this time, the first movable part 3 (reflecting mirror 10) also swings around the Y-axis together with the second movable part 4.

[0049] On the other hand, when a drive current for resonant operation is applied to the coil 15 via external terminals 27 and 28 and wiring 23 and 24, a Lorentz force (driving force) acts on the coil 15 through interaction with the magnetic field generated by the magnetic field generating part M. In addition to this Lorentz force, the first movable part 3 (reflector 10) can be made to resonate around the X-axis by utilizing the resonance of the first movable part 3 at the resonant frequency. Specifically, when a drive current with a frequency equal to the resonant frequency of the first movable part 3 around the X-axis is input to the coil 15, the second movable part 4 vibrates slightly around the X-axis at that frequency. By transmitting this vibration to the first movable part 3 via the first connecting parts 5 and 6, the first movable part 3 can be made to oscillate around the X-axis at that frequency.

[0050] The actuator device 1 also includes: a package 40 for accommodating the support portion 2, the first movable portion 3, the second movable portion 4, a pair of first connecting portions 5 and 6, a pair of second connecting portions 7 and 8, and the magnetic field generating portion M. Figure 4 The package 40 is hermetically sealed. The package 40 has a main body 41 that houses the actuator device 1, and a transparent window member 42 configured to block the opening 41a of the main body 41. Light reflected by the actuator device 1 passes through the window member 42 and enters the reflecting surface 10.

[0051] When the first movable part 3 oscillates around the X-axis and the second movable part 4 oscillates around the Y-axis, due to the torsional deformation of the first connecting parts 5 and 6 and the second connecting parts 7 and 8, stress is repeatedly generated in the connecting portion P1 between the first connecting parts 5 and 6 and the second movable part 4, and in the connecting portion P2 between the second connecting parts 7 and 8 and the second movable part 4. Because this stress acts on the coils 14 and 15 and the wiring 21-24 (metal components) disposed in the connecting portions P1 and P2, the coils 14 and 15 and the wiring 21-24 are plastically deformable. In particular, because the first movable part 3 resonates around the X-axis, large stress is repeatedly generated in the connecting portion P1, and the coils 14 and 15 disposed in the connecting portion P1 are easily plastically deformed. As coils 14 and 15 undergo repeated plastic deformation, work hardening progresses, and the viscous resistance of the first movable part 3 vibrating around the X-axis and the viscous resistance of the second movable part 4 vibrating around the Y-axis may gradually decrease. Therefore, in the manufacturing method of the actuator device 1 of this embodiment, the viscous resistance is reduced in advance by swinging the first movable part 3 and the second movable part 4 for a predetermined time before leaving the factory.

[0052] [Manufacturing method of actuator device]

[0053] Reference Figures 3-6The manufacturing method (inspection method) of actuator device 1 will be described. First, a preparation process (step S1) for preparing multiple actuator devices 1 is performed. In the preparation process, the actuator device 1 is prepared by processing an SOI substrate, for example, using MEMS technology (patterning, etching, etc.). The actuator device 1 prepared in the preparation process is hermetically sealed by package 40.

[0054] Next, a preliminary inspection process (step S2) is performed to confirm the characteristics of each actuator device 1. In this preliminary inspection process, for example, the following are obtained: the resonant frequency of the first movable part 3 vibrating about the X-axis; the value of the drive current applied to the coil 15 to make the first movable part 3 oscillate about the X-axis at a target swing angle (e.g., 20°); the back electromotive force generated in the coil 15 when the first movable part 3 oscillates about the X-axis at that swing angle; and the value of the drive current applied to the coil 14 to make the second movable part 4 oscillate about the Y-axis at a target swing angle (e.g., 12°). The target swing angle refers to the optical swing angle.

[0055] In the pre-inspection process, each actuator device 1 is connected to a computer to verify its characteristics. For example, actuator devices 1 are set one by one in a characteristic inspection device to verify their characteristics. The pre-inspection process also verifies whether each actuator device 1 operates. The pre-inspection process can be omitted when the characteristics of the actuator devices 1 are known in advance. The following oscillation process, acquisition process, and judgment process are performed on each actuator device 1.

[0056] Next, a swinging process (aging process) is performed to swing the first movable part 3 and the second movable part 4 for a predetermined time (step S3). In the swinging process, for example... Figure 4 As shown, multiple (e.g., 24) actuator devices 1 are arranged on the substrate 50. In the oscillation process, the first movable part 3 oscillates around the X-axis and the second movable part 4 oscillates around the Y-axis for a predetermined time. For example, the first movable part 3 oscillates around the X-axis to a target oscillation angle of 20°, and the second movable part 4 oscillates around the Y-axis to a target oscillation angle of 12°. The drive current values ​​used to oscillate the first movable part 3 and the second movable part 4 to the target oscillation angles are values ​​obtained in the pre-inspection process. In the oscillation process, the drive current values ​​are controlled such that the oscillation angle of the first movable part 3 around the X-axis becomes the target oscillation angle by using feedback control of the back electromotive force. The oscillation of the second movable part 4 around the Y-axis is controlled without feedback control.

[0057] The target swing angles of the first movable part 3 and the second movable part 4 correspond, for example, to the maximum recommended operating angle. The larger the swing angle, the more easily the coils 14 and 15 become work-hardened due to plastic deformation. By operating at the upper limit of the range usable by the customer, changes in vibration characteristics at the customer's location can be effectively suppressed. The specified time is, for example, 250 hours. The duration for which the first movable part 3 and the second movable part 4 swing is determined, for example, through experimentation or simulation.

[0058] In the oscillation process, the first movable part 3 and the second movable part 4 oscillate at a certain temperature. For example, by being placed in a constant temperature bath, the ambient temperature of the actuator device 1 is maintained at 60°C. This ambient temperature corresponds to the upper limit of the maximum recommended operating temperature. The higher the ambient temperature, the more easily the coils 14 and 15 are work-hardened due to plastic deformation. By operating at the upper limit of the range that is usable by the customer, changes in vibration characteristics at the customer's location can be effectively suppressed.

[0059] Furthermore, during the oscillation process, the first movable part 3 and the second movable part 4 oscillate under a certain pressure. The atmospheric pressure of the first movable part 3 and the second movable part 4 is maintained constant by the hermetically sealed encapsulation 40. For example, the encapsulation 40 is depressurized to a vacuum state.

[0060] Furthermore, during the oscillation process, the first movable part 3 and the second movable part 4 are oscillating while the temperatures of the first movable part 3, the second movable part 4, the pair of first connecting parts 5 and 6, and the pair of second connecting parts 7 and 8 are each higher than the temperature of the support part 2. In this example, the temperatures of the first movable part 3, the second movable part 4, the pair of first connecting parts 5 and 6, and the pair of second connecting parts 7 and 8 are increased by the heat generated by the coils 14 and 15. For example, when energized, the temperature of the coils 14 and 15 is high, exceeding 200°C. This promotes a reduction in viscous resistance.

[0061] Figure 5 This is a diagram illustrating an example of temperature distribution in a swinging process. Figure 5 The actuator device 1A shown has the same structure as the actuator device 1 described above, except that the shapes of the first movable part 3 and the second movable part 4 are different, and that the coil 15 is disposed in the first movable part 3 instead of the second movable part 4. In the actuator device 1A, the wirings 23 and 24 have portions formed on a pair of first connecting portions 5 and 6. In the actuator device 1A, when the first movable part 3 oscillates, the coil 14 and the wirings 23 and 24 formed near the connecting portion P1 are subjected to particularly large stresses, and work hardening of the coil 14 and the wirings 23 and 24 is easily achieved. Figure 5In the diagram, the configuration area R1 where coil 14 is arranged and the configuration area R2 where coil 15 is arranged are shown in cross-section. In this example, a drive current of 14mA is applied to coil 15, and a drive current of 30mA is applied to coil 14 to drive actuator device 1A. The ambient temperature is set to 25°C, and the atmospheric pressure is set to normal pressure (1 atmosphere).

[0062] like Figure 5 As shown, point a is designated as the annular portion 3b of the first movable part 3, point b is designated as the second movable part 4, point c is designated as the reflective mirror 10 (the main body portion 3a of the first movable part 3), point d is designated as the support portion 2, point e is designated as the first connecting portion 5, and point f is designated as the second connecting portion 7. When the actuator device 1A is driven, the temperatures of points a to f are 89.6°C, 104.4°C, 94.6°C, 41.5°C, 75.2°C, and 146.1°C, respectively. Thus, the temperatures of the first movable part 3, the second movable part 4, the pair of first connecting portions 5 and 6, and the pair of second connecting portions 7 and 8 are all higher than the temperature of the support portion 2 (41.5°C).

[0063] Figure 6 This is a graph illustrating an example of the relationship between the action time and the rate of change of the drive current value. Figure 6 In the example, actuator device 1 was used. Similar to the conditions described above, the target swing angle of the first movable part 3 about the X-axis was set to 20°, and the target swing angle of the second movable part 4 about the Y-axis was set to 12°. The ambient temperature was set to 60°C, and the operating time was set to 250 hours. Figure 6 The vertical axis represents the rate of change of the driving current value applied to the coil 15 in order to make the first movable part 3 swing about the X-axis to the target swing angle. This driving current value decreases as the viscous resistance of the vibration of the first movable part 3 about the X-axis decreases. The rate of change of the driving current value refers to the ratio of the difference between the current driving current value and the driving current value at the start of the operation to the driving current value at the start of the operation.

[0064] from Figure 6 It can be seen that the drive current value fluctuates significantly at the beginning of the operation, but the fluctuation decreases as the operation time progresses. Therefore, it can be concluded that by implementing the oscillation process, the fluctuation of the drive current value over the course of use can be suppressed.

[0065] After the oscillation process, a step (step S4) is performed to obtain parameters related to the viscous resistance of the vibration of the first movable part 3 around the X-axis. In this example, the parameter obtained is the value of the drive current applied to the coil 15 to make the first movable part 3 oscillate around the X-axis to the target oscillation angle (20°). The ambient temperature is set to, for example, 25°C.

[0066] Next, a determination process (step S5) is performed to determine whether the actuator device 1 is qualified based on the value of the parameter obtained in the acquisition process. In the determination process, when the difference (absolute value) between the parameter obtained in the acquisition process and the reference value of the parameter corresponding to the start time of the swing process is greater than or equal to a specified value in the direction of decreasing viscous resistance, the actuator device 1 is determined to be qualified. When the difference is less than the specified value, the actuator device 1 is determined to be unqualified. For example, the qualified actuator device 1 is shipped out, and the unqualified actuator device 1 is excluded without being shipped out.

[0067] In this example, the drive current value at the disclosure time point of the swing process (the drive current value obtained in the pre-inspection process) is set as the reference value, and the specified value is set to 2%. When the change rate of the drive current value is 2% or more (when the drive current value decreases by 2% or more), the actuator device 1 is determined to be qualified as the viscous resistance decreases. On the other hand, when the change rate of the drive current value is less than 2%, the actuator device 1 is determined to be unqualified. The change rate of the drive current value is the ratio of the difference between the drive current value obtained in the acquisition process and the drive current value at the start time point of the swing process to the drive current value at the start time point of the swing process. In addition, in this example, the change rate of the parameter is compared with the specified value (threshold value), but it is also possible to compare the difference between the drive current value obtained in the acquisition process and the drive current value at the start time point of the swing process with the specified value. Through the above process, the actuator device 1 with a pre-reduced viscous resistance can be obtained.

[0068] [Function and Effect]

[0069] In the manufacturing method of actuator device 1, after the oscillation process of oscillating the first movable part 3 around the X-axis for a predetermined time, an acquisition process is performed to obtain the value of a parameter related to the viscous resistance of the vibration of the first movable part 3 around the X-axis. Furthermore, if the difference between the parameter obtained in the acquisition process and the reference value of that parameter corresponding to the start time of the oscillation process is greater than or equal to a predetermined value in the direction of decreasing viscous resistance, actuator device 1 is determined to be qualified; if the difference is less than the predetermined value, actuator device 1 is determined to be unqualified. For example, actuator device 1 that is determined to be qualified is shipped, and actuator device 1 that is determined to be unqualified is not shipped. By reducing the viscous resistance in advance by oscillating the first movable part 3 and the second movable part 4 for a predetermined time before shipping, changes in the vibration characteristics of the first movable part 3 and the second movable part 4 at the customer's location can be suppressed, thereby stabilizing the quality of actuator device 1. Furthermore, in actuator device 1, there may be cases where the viscous resistance does not decrease even after the first movable part 3 and the second movable part 4 are oscillated for a specified time. However, by determining that actuator device 1 with a difference between the obtained parameters and the reference value exceeding a specified value is qualified, only actuator device 1 with reduced viscous resistance can be shipped from the factory. As a result, the quality of actuator device 1 can be further stabilized. Therefore, according to the manufacturing method of actuator device 1, actuator device 1 with stable quality can be obtained.

[0070] Further explanation is needed regarding the possibility that in actuator device 1, even if the first movable part 3 and the second movable part 4 are oscillating for a specified time, the viscous resistance may not decrease. The viscous resistance of the vibration of the first movable part 3 and the second movable part 4 varies not only due to the work hardening of the coils 14 and 15 (metal components) but also due to changes in air resistance. Air resistance varies depending on air pressure and temperature. Therefore, for example, sometimes during the oscillation process, if the vacuum level inside the package 40 decreases and the atmospheric pressure increases, the increase in viscous resistance caused by air resistance exceeds the decrease in viscous resistance caused by the work hardening of the coils 14 and 15, resulting in an increase in total viscous resistance. In addition, viscous resistance may also vary due to structural defects. For this reason, in actuator device 1, there may be a situation where even if the first movable part 3 and the second movable part 4 are oscillating for a specified time, the viscous resistance does not decrease. On the other hand, according to the above-described manufacturing method of actuator device 1, actuator device 1 with a good sealing condition of package 40 can be deemed qualified and shipped.

[0071] The parameters are related to the driving current value used to obtain the specified swing angle. Therefore, the variation in viscous resistance can be appropriately controlled.

[0072] During the oscillation process, the first movable part 3 and the second movable part 4 are oscillated while the temperatures of the first movable part 3, the second movable part 4, the pair of first connecting parts 5 and 6, and the pair of second connecting parts 7 and 8 are higher than the temperature of the support part 2. This effectively reduces viscous resistance.

[0073] In the oscillation process, the first movable part 3 and the second movable part 4 are oscillated at a certain temperature. Thus, for example, by performing the oscillation process at the same temperature as the customer's operating environment, changes in the vibration characteristics of the first movable part 3 and the second movable part 4 at the customer's location can be reliably suppressed.

[0074] During the oscillation process, the first movable part 3 and the second movable part 4 are oscillated under a certain pressure. This suppresses the change in viscous resistance caused by changes in atmospheric pressure and allows for appropriate control of the change in viscous resistance caused by the work hardening of coils 14 and 15 and wiring 21-24 (metal materials that are repeatedly plastically deformed by driving).

[0075] For each of the multiple actuator devices 1, a swinging process, a receiving process, and a judgment process are performed. This allows for the efficient manufacture of actuator devices 1 with consistent quality.

[0076] By generating coils 14 and 15 to drive the first movable part 3 and the second movable part 4 to swing, a metal member subjected to stress is constructed. This allows for the generation of driving forces for the first movable part 3 to swing about the X-axis and the second movable part 4 to swing about the Y-axis. As a result, the quality of the actuator device 1 equipped with coils 14 and 15 can be stabilized.

[0077] Coils 14 and 15 are embedded in groove 31. In this case, the cross-sectional area of ​​coils 14 and 15 becomes larger, and coils 14 and 15 are prone to work hardening due to repeated plastic deformation. However, according to the manufacturing method of actuator device 1, even under such circumstances, it is possible to suppress the change in vibration characteristics of the first movable part 3 at the customer's location.

[0078] The actuator device 1 is hermetically sealed and includes a package 40 that houses the support portion 2, the first movable portion 3, the second movable portion 4, a pair of first connecting portions 5 and 6, and a pair of second connecting portions 7 and 8. This suppresses changes in viscous resistance caused by variations in atmospheric pressure and appropriately controls changes in viscous resistance caused by work hardening of the coils 14 and 15.

[0079] In the oscillation process, the first movable part 3 oscillates around the X-axis and the second movable part 4 oscillates around the Y-axis for a predetermined time. This allows the oscillation process to be performed under the same operating conditions as the customer's environment, reliably suppressing changes in the vibration characteristics of the first movable part 3 and the second movable part 4 at the customer's location. Furthermore, while oscillating the movable parts around multiple axes increases the drive current and raises the ambient temperature, the manufacturing method of the actuator device 1 ensures that even under such conditions, changes in the vibration characteristics of the first movable part 3 and the second movable part 4 at the customer's location can be suppressed.

[0080] During the oscillation process, the first movable part 3 is made to resonate. In this case, the stress acting on the coils 14 and 15 increases, and the coils 14 and 15 are prone to work hardening due to repeated plastic deformation. However, according to the manufacturing method of the actuator device 1, even under such circumstances, the change in the vibration characteristics of the first movable part 3 and the second movable part 4 at the customer's location can be suppressed.

[0081] The viscous resistance to the vibration of the first movable part 3 and the second movable part 4 can be varied not only by the work hardening of the coils 14 and 15, but also by the work hardening of the wiring 21 to 24 disposed in the connecting portions P1 and P2. That is, in the above embodiment, the wiring 21 to 24 can also be configured as a metal member subjected to stress when the first movable part 3 oscillates around the X-axis and the second movable part 4 oscillates around the Y-axis. According to the manufacturing method of the actuator device 1, the quality of the actuator device 1 having wiring 21 to 24 electrically connected to the coils 14 and 15 can be stabilized.

[0082] In addition, wiring 21 to 24 is embedded in groove 31. In this case, the cross-sectional area of ​​wiring 21 to 24 becomes larger, and wiring 21 to 24 is prone to work hardening due to repeated plastic deformation. However, according to the manufacturing method of actuator device 1, even under such circumstances, changes in the vibration characteristics of the first movable part 3 and the second movable part 4 at the customer can be suppressed.

[0083] [Variation Example]

[0084] This invention is not limited to the embodiments described above. For example, the materials and shapes of the various structures are not limited to those described above, and various materials and shapes can be used.

[0085] Alternatively, the reflective mirror 10 can be configured such that stress is applied when the first movable part 3 oscillates around the X-axis and the second movable part 4 oscillates around the Y-axis. In this case, the viscous resistance to the vibration of the first movable part 3 and the second movable part 4 can be varied not only by the work hardening of the coils 14 and 15 and the wiring 21 to 24, but also by the work hardening of the reflective mirror 10. That is, the reflective mirror 10 can also be a metal member for stress application when the first movable part 3 oscillates around the X-axis and the second movable part 4 oscillates around the Y-axis. This metal member can also be composed of at least one of the coils 14 and 15, the wiring 21 to 24, and the reflective mirror 10.

[0086] The driving element is not limited to coils 14 and 15; for example, it can be a piezoelectric element. Coils 14 and 15 can also be formed on the surface of the second movable part 4, instead of being formed in the slot 31. At least a portion of the wiring 21 to 24 can also be configured as surface wiring formed on the surface of the support part 2, the second movable part 4, or the second connecting parts 7 and 8. Coil 15 can also be provided on the first movable part 3. The operation of the first movable part 3 can also be a linear operation (non-resonant operation). The second movable part 4 and the second connecting parts 7 and 8 can also be omitted. In this case, the first movable part 3 can also be directly connected to the support part 2 through the first connecting parts 5 and 6. In this case, the operation of the first movable part 3 can be a resonant operation or a linear operation. That is, in the above embodiment, the actuator device 1 has a resonant axis (high-speed axis, X-axis) and a linear axis (low-speed axis, Y-axis), but the actuator device 1 can also have only one of the resonant axis or the linear axis. The first axis of the first movable part 3 and the second axis of the second movable part 4 can intersect at an angle other than perpendicular, or they can be parallel to each other, or they can be located on the same straight line. The actuator device 1 can also be a support (substrate), a connecting part, and a metal reflector made of metal material for the movable part.

[0087] The parameter is not limited to the drive current value used to obtain the specified swing angle; it can also be a parameter related to the Q-factor, resonant frequency, or the swing angle when the specified drive current value is applied. In this case, the change in viscous resistance can also be appropriately controlled. The parameter can be these values ​​themselves, or values ​​that vary based on these values. On the other hand, in the case of the actuator device 1 described above, it is preferable to use the drive current value as the parameter. (Refer to...) Figure 7 and Figure 8 To elaborate further on this point.

[0088] Figure 7 This is a diagram showing the vibration model of actuator device 1. Figure 7 In this model, actuator device 1 is modeled using a damped vibration system model. Figure 7In this model, m represents mass, k represents spring constant, and c represents damping coefficient. The resonant frequency ω of this model is... d It is represented by equation (1).

[0089]

Number 1

[0090]

[0091] In equation (1), ω0 is the natural angular vibration frequency, as shown in equation (2), which is represented by the inertial torque J and the spring constant k. The natural angular vibration frequency ω0 is determined by the design dimensions and the mechanical properties of the materials used, and is almost unaffected by aging.

[0092]

Number 2

[0093]

[0094] The relationship between the attenuation ratio ζ and the Q value is expressed by equation (3).

[0095]

Number 3

[0096]

[0097] As an example, in actuator device 1, the Q value is extremely high, approximately 10,000. Therefore, the attenuation ratio ζ becomes extremely small, and even with a slight change in the Q value, the resonant frequency ω... d It also remains almost unchanged.

[0098] The relationship between the driving current value I and the Q value is expressed by equation (4).

[0099]

Number 4

[0100]

[0101] In equation (4), θ is the swing angle, and T (I) This is the torque given a driving current of I, where Q is the value of Q. Therefore, when the swing angle θ and the spring constant k are set constant, the torque T... (I) The relationship with Q value is expressed by equation (5), and the torque T (I) It has an inverse proportional relationship with the Q value.

[0102]

Number 5

[0103]

[0104] In addition, the relationship between the attenuation ratio ζ and the damping coefficient c, which is a physical property value representing the magnitude of viscous resistance, is expressed by equation (6).

[0105]

Number 6

[0106]

[0107] In equation (6), c c It is the critical damping coefficient, a constant determined by the inertial torque J and the spring constant k. Therefore, according to the above relationship, when the damping coefficient c decreases due to aging, the attenuation ratio ζ decreases, and the Q value increases. On the other hand, the torque T, which is inversely proportional to the Q value... (I) The driving current value I decreases. That is, when the viscous resistance decreases, the Q value increases, the driving current value used to obtain the specified swing angle decreases, and the swing angle increases when the specified driving current is applied.

[0108] Reference Figure 8 The method for calculating the Q value using the half-width ratio method is explained. This is achieved by changing the frequency while keeping the drive current at a constant value. Figure 8 The frequency response characteristics of the swing angle are shown. Based on the obtained data, by measuring the frequency f0 (resonant frequency) where the swing angle is at its maximum and the frequencies f1 and f2 where the swing angle is -3dB (approximately 0.7 times) of the maximum swing angle, the Q value can be calculated using Q = f0 / (f2-f1). The half-width method is applicable to cases where the frequency response characteristics are approximately symmetrical. In the actuator device 1 described above, since the frequency response has an asymmetrical shape with the peak tilting to the right, it is difficult to accurately calculate the Q value using the half-width method. Therefore, in the manufacturing method of the actuator device 1 described above, the reduction in viscous resistance is evaluated using the drive current value (torque), which is an inversely proportional parameter to the Q value.

[0109] Furthermore, in the manufacturing method of the actuator device 1 described above, the parameter can also be the swing angle when a predetermined drive current value is applied. For example, the actuator device 1 can be continuously operated while the drive current value is set to a certain value, and the change in the swing angle can be observed. However, it is preferable to continuously operate the actuator device 1 with the drive current value and the swing angle set to a certain value, so that the aging conditions do not change due to the change in the swing angle. In addition, when the first movable part 3 operates linearly without resonant operation, the Q value can be easily measured, so the Q value can also be used as a parameter.

[0110] [Explanation of Symbols]

[0111] 1, 1A…Actuator device, 2…Support, 3…First movable part, 4…Second movable part, 5, 6…First connecting part, 7, 8…Second connecting part, 14, 15…Coil (driving element), 21~24…Wiring, 40…Package.

Claims

1. A method for manufacturing an actuator device, wherein, In order, they include: The preparation process includes preparing an actuator device, which comprises: a support portion, a movable portion, a connecting portion that connects the movable portion to the support portion in such a way that the movable portion can swing about a predetermined axis, and a metal member that is configured to be subjected to stress when the movable portion swings about the axis. The oscillation process causes the movable part to oscillate around the axis for a specified time. The process involves obtaining parameters related to the viscous resistance of the vibration of the movable part about the axis; and In the determination process, if the difference between the parameter obtained in the acquisition process and the reference value of the parameter corresponding to the start time of the swing process is above a predetermined value in the direction of decreasing viscous resistance, the actuator device is determined to be qualified; if the difference is less than the predetermined value, the actuator device is determined to be unqualified.

2. The method for manufacturing the actuator device according to claim 1, wherein, The parameters are one or more of the following: Q value, resonant frequency, drive current value used to obtain a specified swing angle, or swing angle under the condition of applying a specified drive current.

3. The method for manufacturing the actuator device according to claim 1, wherein, In the swinging process, the movable part is swung while the temperature of the movable part and the connecting part is higher than the temperature of the supporting part.

4. The method for manufacturing the actuator device according to claim 2, wherein, In the swinging process, the movable part is swung while the temperature of the movable part and the connecting part is higher than the temperature of the supporting part.

5. The method for manufacturing the actuator device according to any one of claims 1 to 4, wherein, In the swinging process, the movable part is made to swing at a certain temperature.

6. The method for manufacturing the actuator device according to any one of claims 1 to 4, wherein, In the swinging process, the movable part is made to swing under a certain pressure.

7. The method for manufacturing the actuator device according to claim 5, wherein, In the swinging process, the movable part is made to swing under a certain pressure.

8. A method for manufacturing an actuator device according to any one of claims 1 to 4, wherein, In the preparation process, a plurality of the actuator devices are prepared. The oscillation process, the acquisition process, and the determination process are performed on each of the plurality of actuator devices.

9. The method for manufacturing the actuator device according to claim 5, wherein, In the preparation process, a plurality of the actuator devices are prepared. The oscillation process, the acquisition process, and the determination process are performed on each of the plurality of actuator devices.

10. The method for manufacturing the actuator device according to claim 6, wherein, In the preparation process, a plurality of the actuator devices are prepared. The oscillation process, the acquisition process, and the determination process are performed on each of the plurality of actuator devices.

11. The method for manufacturing the actuator device according to claim 7, wherein, In the preparation process, a plurality of the actuator devices are prepared. The oscillation process, the acquisition process, and the determination process are performed on each of the plurality of actuator devices.

12. The method for manufacturing the actuator device according to any one of claims 1 to 4, wherein, The actuator device prepared in the preparation process includes a coil that generates a driving force for oscillating the movable part, the coil constituting the metal member.

13. The method for manufacturing the actuator device according to claim 5, wherein, The actuator device prepared in the preparation process includes a coil that generates a driving force for oscillating the movable part, the coil constituting the metal member.

14. The method for manufacturing the actuator device according to claim 6, wherein, The actuator device prepared in the preparation process includes a coil that generates a driving force for oscillating the movable part, the coil constituting the metal member.

15. The method for manufacturing the actuator device according to claim 7, wherein, The actuator device prepared in the preparation process includes a coil that generates a driving force for oscillating the movable part, the coil constituting the metal member.

16. The method for manufacturing the actuator device according to claim 8, wherein, The actuator device prepared in the preparation process includes a coil that generates a driving force for oscillating the movable part, the coil constituting the metal member.

17. The method for manufacturing the actuator device according to claim 9, wherein, The actuator device prepared in the preparation process includes a coil that generates a driving force for oscillating the movable part, the coil constituting the metal member.

18. The method for manufacturing the actuator device according to claim 10, wherein, The actuator device prepared in the preparation process includes a coil that generates a driving force for oscillating the movable part, the coil constituting the metal member.

19. The method for manufacturing the actuator device according to claim 11, wherein, The actuator device prepared in the preparation process includes a coil that generates a driving force for oscillating the movable part, the coil constituting the metal member.

20. The method for manufacturing the actuator device according to claim 12, wherein, The coil is embedded in the groove.

21. The method for manufacturing the actuator device according to claim 13, wherein, The coil is embedded in the groove.

22. The method for manufacturing the actuator device according to claim 14, wherein, The coil is embedded in the groove.

23. The method for manufacturing the actuator device according to claim 15, wherein, The coil is embedded in the groove.

24. The method for manufacturing the actuator device according to claim 16, wherein, The coil is embedded in the groove.

25. The method for manufacturing the actuator device according to claim 17, wherein, The coil is embedded in the groove.

26. The method for manufacturing the actuator device according to claim 18, wherein, The coil is embedded in the groove.

27. The method for manufacturing the actuator device according to claim 19, wherein, The coil is embedded in the groove.

28. A method for manufacturing an actuator device according to any one of claims 1 to 4, wherein, The actuator device prepared in the preparation process includes: a drive element that generates a driving force for oscillating the movable part, and wiring electrically connected to the drive element, the wiring constituting the metal component.

29. The method for manufacturing the actuator device according to claim 28, wherein, The wiring is embedded in the groove.

30. A method for manufacturing an actuator device according to any one of claims 1 to 4, wherein, The actuator device prepared in the preparation process further includes: an encapsulation that hermetically seals and accommodates the support, the movable part, the connecting part, and the metal component.

31. A method for manufacturing an actuator device according to any one of claims 1 to 4, wherein, In the actuator device prepared in the preparation process. The movable part includes: a first movable part and a second movable part. The connecting portion includes: a first connecting portion that connects the first movable portion to the second movable portion in such a way that the first movable portion can swing about a first axis; and a second connecting portion that connects the second movable portion to the support portion in such a way that the second movable portion can swing about a second axis. In the swinging process, the first movable part swings around the first axis for the specified time, and the second movable part swings around the second axis.

32. The method for manufacturing the actuator device according to any one of claims 1 to 4, wherein, During the swinging process, the movable part is made to resonate.

33. The method for manufacturing the actuator device according to any one of claims 1 to 4, wherein, Between the preparation step and the oscillation step, there is also a pre-check step to obtain the reference value.

34. The method for manufacturing the actuator device according to any one of claims 1 to 4, wherein, In the preparation process, a plurality of the actuator devices are prepared. In the oscillation process, the plurality of actuator devices are arranged on a common substrate.

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