JP4873560B2 - Optical scanning device - Google Patents

Description

  The present invention relates to an optical scanning device that deflects a light beam from a light source by reciprocally vibrating a mirror member, and in particular, reciprocally vibrates a mirror member supported by a pair of torsion beams using the torsion beams as a rotation axis. The present invention relates to an optical scanning device.

  An optical scanning device that reciprocally vibrates a mirror member supported by a pair of torsion beams by using the torsion beam as a torsional rotation axis. When the drive frequency is matched with the resonance frequency of the mirror member, the mirror member can be moved with less drive energy. It can be vibrated with a large deflection angle.

  However, the resonance frequency of the mirror member inevitably varies to some extent due to processing variations in the manufacturing process. In addition, the resonance frequency varies depending on changes in the operating environment (temperature, humidity, pressure). For example, as disclosed in Patent Document 4, in a case where the main scanning of an image is divided and performed by a plurality of optical scanning devices arranged in parallel, if the variation in the resonance frequency of the optical scanning device is large, a plurality of light beams This is extremely inconvenient because the scanning device cannot be driven at a common frequency. Therefore, it is desirable to provide the optical scanning device with a resonance frequency adjusting means.

  An example of an optical scanning device provided with a resonance frequency adjusting means is disclosed in Patent Document 1. As shown in FIG. 9, in this optical scanning device, the ends on the fulcrum side of a plurality of bending springs 22 (acting as a torsion beam as a whole) serving as the torsional rotation axis of the mirror member 21 are supported by the inertia part 30. The inertia part 30 is supported on the anchor 60 by a bending spring 32. A comb-like electrode 31 is provided in the inertia part 30, and a comb-like electrode 41 that meshes with the comb-like electrode 31 is provided on the anchor 40. A comb-like electrode 23 is provided on the free end side of the mirror member 21, and a comb-like electrode 51 that meshes with the comb-like electrode 23 is provided on the anchor 50. The operation is as follows. When a driving voltage is applied between the comb-like electrodes 23 and 50, a driving torque is generated, and the mirror member 21 reciprocates. By applying a voltage between the comb-shaped electrodes 31 and 41, an electrostatic force that pulls the inertia part 30 outward is generated. This pulling force acts to increase the spring constant of the bending spring 22. Therefore, the resonance frequency of the mirror member 21 can be adjusted by adjusting the spring constant of the bending spring 22 by adjusting the voltage applied between the comb-shaped electrodes 31 and 41.

  Further, although the basic structure and behavior of the vibration system are different from those of the optical scanning apparatus according to the present invention, an example of an optical scanning apparatus provided with a resonance frequency adjusting means is disclosed in Patent Document 2. This optical scanning device (optical scanner) includes a vibrator formed by connecting a vibrating portion having a mirror surface and a lake bottom portion via an elastic deformation portion, and an excitation device (for example, a piezoelectric element) that applies high-frequency vibration to the fixed portion. The elastic deformation portion is heated or deformed by a heating resistor element or a piezoelectric element provided in the elastic deformation portion, thereby changing the spring constant of the elastic deformation portion and adjusting the resonance characteristics of the vibrator.

  An optical scanning device that uses a piezoelectric element to vibrate a mirror member about a pair of twisted beams as a rotation axis is also known. For example, in Patent Document 3, two pairs of piezoelectric unimorph diaphragms on which piezoelectric elements are formed are connected to a mirror member, and an AC voltage having an opposite phase is applied to the piezoelectric elements of each pair of piezoelectric unimorph diaphragms. An optical scanning device (optical deflector) that reciprocally oscillates a pair of torsion beams (elastic members) as a rotation axis is disclosed.

JP 2005-141229 A Japanese Patent No. 2981600 JP 2005-128147 A JP 2001-228428 A

  In the optical scanning device described in Patent Document 1, the end on the fulcrum side of the bending spring 22 serving as the torsional rotation axis of the mirror member 21 is not fixed but supported by the inertia part 30, and the inertia part 30 is Since it is supported by the bending spring 32, the inertia part 30 also vibrates in response to the reciprocating vibration of the mirror member 21. The vibration around the axis tends to cause a short circuit between the comb-like electrode 31 provided in the inertia part 30 and the fixed comb-like electrode 41, and the resonance frequency (control) is unstable. There is also a risk of becoming. Further, it is generally not preferable that the end of the bending spring 22 on the fulcrum side is not fixed from the viewpoint of the stability of the reciprocating vibration of the mirror member 21. In addition, the chip area of the optical scanning device tends to increase.

  Note that, as in the optical scanning device disclosed in Patent Document 2, the configuration using the heat generating means for adjusting the resonance frequency is generally not preferable because the current for heat generation always flows and the power consumption increases. .

  The present invention has been made in view of the above points, and an object thereof is an optical scanning device of a type in which a mirror member supported by a pair of torsion beams reciprocally vibrates with a torsion beam as a torsion rotation axis. The problem as in the conventional example described in Patent Document 1 is solved, and the resonance frequency can be continuously adjusted within a sufficient range. Even when the mirror member is relatively large, the mirror member can be made large with a low driving voltage. An object of the present invention is to provide an improved optical scanning device which can be vibrated at a deflection angle.

An optical scanning device according to the invention of claim 1 is provided.
An optical scanning device in which a mirror member supported by a pair of torsion beams reciprocally vibrates with the pair of torsion beams as a torsion rotation axis,
The fulcrum end of the torsion beam is fixed to a fixing member,
The non-fixed side ends of a pair of cantilevers that are symmetrically positioned with respect to the torsion beam are coupled to the same portion of the torsion beams, and the fixed side ends of the pair of cantilevers are fixed at positions symmetrical to the torsion beam. Fixed to
A piezoelectric element for generating a driving torque for the mirror member by deforming the cantilever is formed on the cantilever,
The cantilever is formed with a spring portion in the vicinity of the fixed side end thereof,
A first electrode and a second electrode facing each other for generating a force for pulling the cantilever toward its fixed side end are formed on the spring portion and the fixing member of the cantilever, respectively.
The adjustment of the resonance frequency of the mirror member can be adjusted by adjusting the applied voltage between the first and second electrodes facing each other ,
The cantilever is formed on the first silicon substrate side of the SOI substrate, and the torsion beam and the mirror member are formed on the second silicon substrate side of the SOI substrate.

  In this optical scanning device, the end of each torsion beam on the fulcrum side is fixed to a fixed member, so that the vibration of the mirror member is more stable than the structure of Patent Document 1 in which it is not fixed. It is good. Further, compared to the configuration using the electrostatic force between the electrodes for driving as in Patent Document 1, a large driving torque can be generated by applying a low driving voltage to the piezoelectric element. Even if it is large, it can be reciprocated with a large deflection angle. Since the spring part does not vibrate around the axis of the cantilever when the mirror member vibrates, the short circuit between the first and second electrodes can be reliably prevented, and the tensile force acting on the cantilever is stabilized, so that the resonance frequency is also stable. To do.

An optical scanning device according to a second aspect of the present invention provides:
An optical scanning device in which a mirror member supported by a pair of torsion beams reciprocally vibrates with the pair of torsion beams as a torsion rotation axis,
The fulcrum end of the torsion beam is fixed to a fixing member,
The non-fixed side ends of a pair of cantilevers that are symmetrically positioned with respect to the torsion beam are coupled to the same portion of the torsion beams, and the fixed side ends of the pair of cantilevers are fixed at positions symmetrical to the torsion beam. Fixed to
A first piezoelectric element for generating a driving torque for the mirror member by deforming the cantilever is formed on the cantilever,
The cantilever is formed with a spring portion in the vicinity of the fixed side end thereof,
A second piezoelectric element for generating a force for pulling the cantilever to its fixed side end by deforming the spring portion of the cantilever is formed in the spring portion of the cantilever,
The resonance frequency of the mirror member can be adjusted by adjusting the applied voltage of the second piezoelectric element ,
The cantilever is formed on the first silicon substrate side of the SOI substrate, and the torsion beam and the mirror member are formed on the second silicon substrate side of the SOI substrate.

  In this optical scanning device, the end of each torsion beam on the fulcrum side is fixed to a fixed member, so that the vibration of the mirror member is more stable than the structure of Patent Document 1 in which it is not fixed. good. Further, compared to the configuration using the electrostatic force between the electrodes for driving as in Patent Document 1, a large driving torque can be generated by applying a low driving voltage to the first piezoelectric element. Even when it is relatively large, it can be reciprocally vibrated with a large deflection angle. Since a large pulling force can be generated by applying a low voltage to the second piezoelectric element, it is easy to expand the adjustment range of the resonance frequency. Further, since the spring portion does not vibrate around the axis of the cantilever when the mirror member vibrates, the tensile force acting on the cantilever is stabilized, so that the resonance frequency is also stabilized.

An optical scanning device according to a third aspect of the present invention provides:
An optical scanning device in which a mirror member supported by a pair of torsion beams reciprocally vibrates with the pair of torsion beams as a torsion rotation axis,
The fulcrum end of the torsion beam is fixed to a fixing member,
The non-fixed side ends of the pair of first cantilevers that are symmetrically positioned with respect to the torsion beam are coupled to the same portion of the torsion beam, and the fixed side ends of the pair of first cantilevers are symmetrical with respect to the torsion beam. Fixed to the fixing member at the position,
The non-fixed side ends of the pair of second cantilevers that are symmetrically positioned with respect to the torsion beam are coupled to the same portion of the torsion beam, and the fixed side ends of the pair of second cantilevers are symmetrical with respect to the torsion beam. Fixed to the fixing member at the position,
A piezoelectric element for generating a driving torque for the mirror member by deforming the first cantilever is formed on the first cantilever,
The second cantilever is formed with a spring portion in the vicinity of its fixed side end,
A first electrode and a second electrode facing each other for generating a force for pulling the second cantilever to its fixed side end are respectively formed on the spring part and the fixing member of the second cantilever,
The resonance frequency of the mirror member can be adjusted by adjusting the applied voltage between the opposed first and second electrodes ,
The first cantilever and the second cantilever are formed on the first silicon substrate side of the SOI substrate, and the torsion beam and the mirror member are formed on the second silicon substrate side of the SOI substrate.

  In this optical scanning device, the end of each torsion beam on the fulcrum side is fixed to a fixed member. Therefore, the vibration of the mirror member is more stable than the structure of Patent Document 1 in which it is not fixed. Is advantageous. Further, compared to the configuration using the electrostatic force between the electrodes for driving as in Patent Document 1, a large driving torque can be generated by applying a low driving voltage to the piezoelectric element. Even if it is large, it can be reciprocated with a large deflection angle. Since the spring portion does not vibrate around the axis of the second cantilever when the mirror member vibrates, a short circuit between the first and second electrodes can be surely prevented, and the tensile force acting on the second cantilever can be stabilized. The resonance frequency is also stabilized. In addition, since the first cantilever for applying the driving torque to the torsion beam and the second cantilever for applying the torque opposite to the driving torque (resonance frequency adjusting torque) to the torsion beam are separated, Torque interference can be prevented.

An optical scanning device according to the invention of claim 4 is provided.
An optical scanning device in which a mirror member supported by a pair of torsion beams reciprocally vibrates with the pair of torsion beams as a torsion rotation axis,
The fulcrum end of the torsion beam is fixed to a fixing member,
The non-fixed side ends of the pair of first cantilevers that are symmetrically positioned with respect to the torsion beam are coupled to the same portion of the torsion beam, and the fixed side ends of the pair of first cantilevers are symmetrical with respect to the torsion beam. Fixed to the fixing member at the position,
The non-fixed side ends of the pair of second cantilevers that are symmetrically positioned with respect to the torsion beam are coupled to the same portion of the torsion beam, and the fixed side ends of the pair of second cantilevers are symmetrical with respect to the torsion beam. Fixed to the fixing member at the position,
A first piezoelectric element for generating a driving torque for the mirror member by deforming the first cantilever is formed on the first cantilever,
The second cantilever is formed with a spring portion in the vicinity of its fixed side end,
A second piezoelectric element for generating a force for pulling the second cantilever to its fixed side end by deforming the spring portion of the second cantilever is formed in the spring portion of the second cantilever;
The resonance frequency of the mirror member can be adjusted by adjusting the applied voltage of the second piezoelectric element ,
The first cantilever and the second cantilever are formed on the first silicon substrate side of the SOI substrate, and the torsion beam and the mirror member are formed on the second silicon substrate side of the SOI substrate.

  In this optical scanning device, the end of each torsion beam on the fulcrum side is fixed to a fixed member. Therefore, the vibration of the mirror member is more stable than the structure of Patent Document 1 in which it is not fixed. Is advantageous. Further, compared to the configuration using the electrostatic force between the electrodes for driving as in Patent Document 1, a large driving torque can be generated by applying a low driving voltage to the first piezoelectric element. Even when it is relatively large, it can be reciprocally vibrated with a large deflection angle. Since a large pulling force can be generated by applying a low voltage to the second piezoelectric element, it is easy to expand the adjustment range of the resonance frequency. Since the spring portion does not vibrate around the axis of the second cantilever when the mirror member vibrates, the tensile force acting on the second cantilever is stabilized, so that the resonance frequency is stabilized. In addition, since the first cantilever for applying the driving torque to the torsion beam and the second cantilever for applying the torque opposite to the driving torque (resonance frequency adjusting torque) to the torsion beam are separated, Torque interference can be prevented.

In the optical scanning device according to any one of claims 1 to 4, the cantilever is formed on the first silicon substrate side of the SOI substrate, and the torsion beam and the mirror member are formed on the second silicon substrate side of the SOI substrate. Thus, for example, by reducing the thickness of the first silicon substrate and increasing the thickness of the second silicon substrate, the cantilever can be reduced in thickness so that the mirror member is less likely to be deformed. There is an advantage that the thickness can be increased.

According to a fifth aspect of the invention, in the optical scanning device according to the first or third aspect of the invention, the first and second electrodes are comb-like electrodes.

Thus, when the first and second electrodes are comb-like electrodes, the facing area between both electrodes is increased, and a larger tensile force can be generated with a low applied voltage, so that the adjustment range of the resonance frequency can be expanded. It becomes easy.

As described above, according to the present invention, the problems of the conventional example described in Patent Document 1 are solved, and the resonance frequency can be continuously adjusted within a sufficient range, and the resonance frequency is stabilized. Even when the mirror member is relatively large, the mirror member can be reciprocally oscillated with a large swing angle with a low driving voltage . The cantilever is reduced in thickness to facilitate deformation, while the mirror member is deformed. It is possible to realize an optical scanning device improved in many respects, such as increasing the thickness so as to be difficult .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In a plurality of drawings referred to in the following description, the same or corresponding reference numerals are used for the same or corresponding elements. Here, the description will be made on the assumption that the optical scanning device of the present invention is manufactured using an SOI (Silicon On Insulator) substrate in which two silicon (Si) substrates are bonded via an insulating film, but the present invention is not limited to this. Instead, for example, an optical scanning device can be manufactured using an SOI substrate or the like in which three or more silicon substrates are bonded.

[First Embodiment]
An optical scanning device according to a first embodiment of the present invention will be described with reference to FIG. 1C is a schematic plan view of the optical scanning device. (A) And (b) is a schematic plan view which shows the element formed in the 1st Si substrate side of the SOI substrate among the components of this optical scanning device, and the element formed in the 2nd Si substrate side. That is, (c) shows a state in which the structure shown in (b) is superimposed on the lower side of the structure shown in (a).

  In this optical scanning device, a mirror mass portion (mirror member) 3 is supported on a frame 1 by a pair of torsion beams 2, and the mirror mass portion 3 can reciprocally vibrate with the pair of torsion beams 2 as a torsion rotation axis. An end on the fulcrum side of the torsion beam 2 is fixed to the frame 1, and the other end is coupled to the mirror mass part 3. The frame 1 includes a frame portion 1a formed on the first Si substrate side and a frame portion 1b formed on the second Si substrate side. The torsion beam 2 and the mirror mass part 3 are integrally formed on the second Si substrate side together with the frame part 1b. A mirror surface is formed on the surface of the mirror mass unit 3.

  The unfixed side ends of a pair of cantilevers 4 having a symmetrical positional relationship with each torsion beam 2 are coupled at the same site. The fixed side ends of the pair of cantilevers 4 are fixed to the frame 1 at positions symmetrical to the torsion beam 2. The cantilever 4 is formed integrally with the frame portion 1a on the first Si substrate side. The two cantilevers 4 forming a pair are formed as a single member whose non-fixed side ends are connected to each other, but each acts as an independent cantilever for the torsion beam 2.

  Each cantilever 4 has a spring portion 4a having a shape branched into two legs in the vicinity of its fixed side end. An outward comb-like electrode 5 is formed on the spring portion 4b. The frame portion 1 b does not exist below the spring portion 4 a and the electrode 5, and the spring portion 4 a can be elastically deformed and can be slightly displaced relative to the frame 1. An inward comb-like electrode 6 is formed at a position of the frame 1 corresponding to the electrode 5 so as to mesh with the electrode 5. The electrode 6 is formed on the first Si substrate side, but is electrically separated from the frame portion 1 a and the cantilever 4 by the separation groove 7. The first Si substrate is a low-resistance substrate (conductor), and can itself serve as an electrode without forming a metal film or the like. A piezoelectric element 8 is formed on each cantilever 4. The deformation direction of each piezoelectric element 8 is the length direction of the cantilever 4.

  The operation of this optical scanning device will be described. For example, a sine wave voltage having an opposite phase is applied as a drive voltage to the piezoelectric element 8 provided on one side of the pair of cantilevers 4 coupled to each torsion beam 2 and the piezoelectric element 8 provided on the other side. Then, in a certain period of the sinusoidal voltage, one cantilever 4 is deformed by bending in a convex direction because the piezoelectric element 8 formed on the upper surface thereof is extended, and the other cantilever 4 is formed by the piezoelectric element 8 formed on the upper surface thereof. In order to shrink, it bends and deforms in the concave direction. In the next cycle of the sine wave voltage, the deformation direction of the pair of cantilevers 4 is reversed. Therefore, the driving torque of the mirror mass unit 3 acts on the torsion beam 2, and the mirror mass unit 3 reciprocally vibrates using the pair of torsion beams 2 as the torsion rotation shaft. That is, the piezoelectric element 8 is a means for generating a driving torque for vibrating the mirror mass unit 3 by deforming the cantilever 4. Since the end on the fulcrum side of each torsion beam 2 is fixed to the frame 1, it is advantageous in terms of vibration stability of the mirror mass portion 3 compared to the structure as in Patent Document 1 where it is not fixed. Yes (the same applies to each embodiment described later). Further, compared to the configuration in which the electrostatic force between the electrodes is used for driving as in Patent Document 1, a large driving torque can be generated with a low driving voltage (voltage applied to the piezoelectric element 8), and the mirror mass unit 3 Can be reciprocally oscillated with a large deflection angle even when is relatively large (this is the same in each embodiment described later).

  When the mirror mass portion 3 is reciprocally oscillating, the cantilever 4 applies a torque as a reaction force to the torsion beam 2 that is torsionally rotated. This torque (referred to as resonance frequency adjustment torque) acts in the direction of increasing the spring constant of the torsion beam 3. When a voltage is applied between the electrodes 5 and 6, the spring portion 4a is pulled toward the electrode 6 by the electrostatic attractive force between the electrodes, so that the resonance frequency adjusting torque increases. As the applied voltage between the electrodes 5 and 6 is increased to increase the electrostatic attractive force between the electrodes, the resonance frequency adjusting torque acting on the torsion beam 2 increases. Therefore, the spring constant of the torsion beam 3 can be adjusted by increasing or decreasing the resonance frequency adjustment torque by increasing or decreasing the applied voltage between the electrodes 5 and 6. Since the vibration resonance frequency of the mirror mass portion 3 is determined by the spring constant of the torsion beam 3, the resonance frequency can be adjusted by adjusting the voltage applied between the electrodes 5 and 6. In addition, since the spring portion 4b does not vibrate around the axis of the cantilever 4 when the mirror mass portion 3 vibrates, the comb-like electrodes 5 and 6 between the electrodes 6 which are problematic in the above-mentioned Patent Document 1 are used. A short circuit can be surely prevented, and since the pulling force (electrostatic attractive force) between the electrodes 5 and 6 is stabilized, a stable resonance frequency adjusting torque can be applied, and the resonance frequency is also stabilized (second to later described). The same applies to the fourth embodiment). In addition, it was confirmed that the resonant frequency can be continuously adjusted within a range of 1% or more with the prototyped optical scanning device (the same applies to each embodiment described later).

As is apparent from the above description, this embodiment corresponds to an embodiment of the invention described in claims 1 and 5 .

  A method for manufacturing the optical scanning device will be described. FIGS. 2-1 and 2-2 are explanatory diagrams of processes, and schematically show the nominal shape in each process corresponding to the A-A ′ cross section of FIG.

  Step (1): On the surface of the SOI substrate where the first Si substrate 101 and the second Si substrate 102 are bonded via an oxide film (insulating film) 103, thermal oxide films 104 and 105 for insulation are formed to a thickness of 0.5 μm, for example. Form a film. The first Si substrate is a low resistance substrate (conductor).

  Step (2): On the thermal oxide film 104, a lower electrode film 106 for forming the piezoelectric element 8, a piezoelectric material film 107 that expands and contracts in the length direction of the cantilever 4 by voltage application, and an upper electrode film 108 are formed. Films are formed in this order. Examples of the material and film thickness of each film are as follows. As the lower electrode film 106, a Ti film having a thickness of 0.05 μm and a Pt film having a thickness of 0.15 μm are formed in this order. A 3 μm thick zirconate titanate (PZT) film is formed as the piezoelectric material film 107. A Pt film having a thickness of 0.15 μm is formed as the upper electrode film 108. As a film formation method, a sputtering method can be used for the lower electrode film and the upper electrode film. As the piezoelectric material film (PZT film) 107, a sputtering method, a CVD (Chemical Vapor Deposition) method, an ion plating method, or the like can be used.

  Step (3): A resist pattern 109 for dry etching the upper electrode film 108 and the PZT film is formed.

  Step (4): The upper electrode film 108 and the piezoelectric material (PZT) film 107 are dry-etched by RIE (Reactive Ion Etching), and then the resist is removed.

  Step (5): A resist pattern for dry etching the lower electrode film 106 and the thermal oxide film 104 is formed.

  Step (6): The lower electrode film 106 and the thermal oxide film 104 are dry-etched by RIE. Thereafter, the resist is removed. Thus, the piezoelectric element 8 was completed.

  Step (7): A resist pattern 111 for forming the cantilever 4 and the comb-like electrodes 5 and 6 by dry etching is formed.

  Step (8): The first Si substrate 101 is dry etched by RIE. Thereafter, the resist is removed.

  Step (9): After removing the exposed oxide film 103, a mirror reflection film 112 is formed to be a mirror surface of the mirror mass unit 3. As the mirror reflection film 112, for example, a 0.05 μm thick Ti film, a 0.05 μm thick Pt film, and a 0.1 μm thick Au film are formed in this order. Here, the stencil mask is used for the sputtering method, but an electrode pad (not shown) can be formed at the same time. A lift-off method can also be used.

  Step (10): A resist pattern 113 for forming the mirror mass portion 3 and the torsion beam 2 by dry etching is formed on the thermal oxide film 105 on the second Si substrate 102 side.

  Step (11): The second Si substrate 102 is dry etched by RIE.

  Step (12): The exposed oxide film 103 is removed, and then the resist is removed.

  Note that the comb-like electrodes 5 and 6 may be flat electrodes as shown in FIG. However, when the electrodes 5 and 6 are comb-shaped, the facing area increases, so that a large electrostatic force and a large resonance frequency adjustment torque can be generated with a lower applied voltage.

[Second Embodiment]
An optical scanning device according to a second embodiment of the present invention will be described with reference to FIG. 4C is a schematic plan view of the optical scanning device. (A) And (b) is a schematic plan view which shows the element formed in the 1st Si substrate side of the SOI substrate among the components of this optical scanning device, and the element formed in the 2nd Si substrate side. That is, (c) shows a state in which the structure shown in (b) is superimposed on the lower side of the structure shown in (a).

  As apparent from a comparison between FIGS. 4A and 4B and FIGS. 1A and 1B, in this embodiment, the torsion beam 2 and the mirror mass portion 3 are also formed on the first Si substrate side. The configuration other than this point is the same as that of the first embodiment. Note that the comb-like electrodes 5 and 6 may be flat electrodes as shown in FIG.

  The method of manufacturing the optical scanning device according to the present embodiment can be easily inferred from the description of the method of manufacturing the optical scanning device according to the first embodiment. Therefore, the description of the manufacturing method of the optical scanning device according to this embodiment is omitted.

  In the present embodiment, substantially all the elements are formed on the first Si substrate, so that the manufacturing process is simplified as compared to the first embodiment. Therefore, when the mirror mass part 3, the torsion beam 2, and the cantilever 4 may have the same thickness, the use of this embodiment is advantageous in terms of the manufacturing process. On the other hand, the manufacturing process of the first embodiment is more complicated than that of the present embodiment, but the cantilever 4 can be easily deformed by making the first Si substrate thinner and the second Si substrate thicker. (The applied voltage of the piezoelectric element 8 can be reduced), and the mirror mass part 3 has an advantage that the thickness can be increased so as not to be deformed.

[Third Embodiment]
An optical scanning device according to a third embodiment of the present invention will be described with reference to FIG. In FIG. 5, (c) is a schematic plan view of the optical scanning device. (A) And (b) is a schematic plan view which shows the element formed in the 1st Si substrate side of the SOI substrate among the components of this optical scanning device, and the element formed in the 2nd Si substrate side. That is, (c) shows a state in which the structure shown in (b) is superimposed on the lower side of the structure shown in (a).

  In this embodiment, each torsion beam 2 is coupled at the same position to the non-fixed side ends of a pair of cantilevers 4 that are symmetrical relative to each other, and another similar pair of cantilevers 14 is not fixed. It is bonded to the side end at the same site. The cantilever 14 is formed on the first Si substrate side. A piezoelectric element 8 for generating a driving torque is formed on the upper surface of the cantilever 14. The other configuration is the same as that of the first embodiment.

  In this embodiment, since the cantilever 14 provided with the piezoelectric element 8 for generating the driving torque and the cantilever 4 related to the generation of the resonance frequency adjusting torque are separated, the interference between the driving torque and the resonance frequency adjusting torque is prevented. There is an advantage that can be suppressed. However, the chip area of the optical scanning device increases as the number of cantilevers increases. Also in this embodiment, the comb-like electrodes 5 and 6 can be formed into flat electrode shapes as shown in FIG.

  The optical scanning device according to the present embodiment can be manufactured in the same manufacturing process as the optical scanning device according to the first embodiment, except that the number of cantilevers is increased.

As is apparent from the above description, this embodiment corresponds to an embodiment of the invention described in claims 3 and 5 . The cantilever 14 corresponds to the first cantilever, and the cantilever 4 corresponds to the second cantilever.

[Fourth Embodiment]
An optical scanning device according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 6C is a schematic plan view of the optical scanning device. (A) And (b) is a schematic plan view which shows the element formed in the 1st Si substrate side of the SOI substrate among the components of this optical scanning device, and the element formed in the 2nd Si substrate side. That is, (c) shows a state in which the structure shown in (b) is superimposed on the lower side of the structure shown in (a).

  As apparent from a comparison between FIGS. 6A and 6B and FIGS. 5A and 5B, in this embodiment, the torsion beam 2 and the mirror mass portion 3 are also formed on the first Si substrate side. The configuration other than this point is the same as that of the third embodiment. Note that the comb-like electrodes 5 and 6 may be flat electrodes as shown in FIG.

  The method of manufacturing the optical scanning device according to the present embodiment can be easily inferred from the description of the method of manufacturing the optical scanning device according to the first embodiment. Therefore, the description of the manufacturing method of the optical scanning device according to this embodiment is omitted.

  In the present embodiment, since substantially all elements are formed on the common first Si substrate side, the manufacturing process is simpler than that of the third embodiment. Therefore, when the mirror mass part 3, the torsion beam part 2, and the cantilevers 4 and 14 may have the same thickness, the use of this embodiment is advantageous in terms of the manufacturing process. On the other hand, the manufacturing process of the third embodiment is more complicated than that of the present embodiment, but the cantilevers 4 and 14 can be easily deformed by making the first Si substrate thinner and the second Si substrate thicker. There are advantages that the thickness can be reduced (the voltage applied to the piezoelectric element 8 can be lowered) and the mirror mass part 3 can be increased in thickness so that it is difficult to deform.

[Fifth Embodiment]
An optical scanning apparatus according to a fifth embodiment of the present invention will be described with reference to FIG. 7C is a schematic plan view of the optical scanning device. (A) And (b) is a schematic plan view which shows the element formed in the 1st Si substrate side of the SOI substrate among the components of this optical scanning device, and the element formed in the 2nd Si substrate side. That is, (c) shows a state in which the structure shown in (b) is superimposed on the lower side of the structure shown in (a).

  In this embodiment, an elastic deformation portion 4b that connects the two legs is formed on the spring portion 4a of the cantilever 4 formed on the first Si substrate. The frame portion 1b does not exist below the elastically deformable portion 4b. A piezoelectric element 18 is formed on the elastic deformation portion 4b. The deformation direction of the piezoelectric element 18 is the length direction of the elastic deformation portion 4b. The electrodes 5 and 6 in the first embodiment are not provided. Other configurations are the same as those of the first embodiment. The manufacturing method of the optical scanning device according to the present embodiment may be the same as that of the optical scanning device according to the first embodiment, and thus description thereof will not be repeated.

  The operation will be described. By applying a driving voltage to the piezoelectric element 8 to generate a driving torque, the mirror mass unit 3 reciprocally vibrates about the torsion beam 2 as a torsion rotating shaft. When a voltage is applied to the piezoelectric element 18 to cause the piezoelectric element 18 to expand or contract, the elastically deforming portion 4b bends in the convex direction or the concave direction, thereby attracting the two legs of the spring portion 4b. As a result of the deformation in the direction and the spring portion 4b being pulled outward, the resonance frequency adjustment torque acting on the torsion beam 2 increases. As the voltage applied to the piezoelectric element 18 increases or decreases, the force pulling the spring portion 4b increases or decreases, and the resonance frequency adjustment torque also increases or decreases. Therefore, by adjusting the voltage applied to the piezoelectric element 18, the spring constant of the torsion beam 2 can be adjusted, and the vibration resonance frequency of the mirror mass part 3 can be adjusted. In the present embodiment, a large resonance frequency adjusting torque can be generated by applying a voltage lower than the applied voltage between the electrodes 5 and 6 in the first to fourth embodiments to the piezoelectric element 18. Further, since the resonance frequency adjustment torque can be changed in a wider range, the adjustment range of the resonance frequency can be easily expanded.

As is apparent from the above description, this embodiment corresponds to an embodiment of the invention described in claim 2 . The piezoelectric element 8 corresponds to the first piezoelectric element, and the piezoelectric element 18 corresponds to the second piezoelectric element.

In addition, the form which provides the elastic deformation part and piezoelectric element similar to the case of this embodiment to the spring part 4a of the cantilever 4 in the said 3rd Embodiment (FIG. 5) is also possible. Such an embodiment corresponds to an embodiment of the invention described in claim 4 .

[Sixth Embodiment]
An optical scanning device according to a sixth embodiment of the present invention will be described with reference to FIG. 8C is a schematic plan view of the optical scanning device. (A) And (b) is a schematic plan view which shows the element formed in the 1st Si substrate side of the SOI substrate among the components of this optical scanning device, and the element formed in the 2nd Si substrate side. That is, (c) shows a state in which the structure shown in (b) is superimposed on the lower side of the structure shown in (a).

  As apparent from a comparison between FIGS. 8A and 8B and FIGS. 7A and 7B, in this embodiment, the torsion beam 2 and the mirror mass portion 3 are also formed on the first Si substrate side. The configuration other than this point is the same as that of the fifth embodiment. In the present embodiment, since substantially all elements are formed on the first Si substrate side, the manufacturing process is simplified as compared to the fifth embodiment. Therefore, when the mirror mass part 3, the torsion beam part 2, and the cantilevers 4 and 14 may have the same thickness, the use of this embodiment is advantageous in terms of the manufacturing process. On the other hand, in the fifth embodiment, the manufacturing process is more complicated than in this embodiment, but the cantilevers 4 and 14 are reduced in thickness so as to be easily deformed (the applied voltage of the piezoelectric elements 8 and 18 is lowered). The mirror mass part 3 has an advantage that the thickness can be increased so that the mirror mass part 3 is not easily deformed.

  The method of manufacturing the optical scanning device according to the present embodiment can be easily inferred from the description of the method of manufacturing the optical scanning device according to the first embodiment, and therefore the description thereof will not be repeated.

In addition, the form which provides the elastic deformation part and piezoelectric element similar to the case of this embodiment to the spring part 4a of the cantilever 4 in the said 4th Embodiment (FIG. 6) is also possible.

  The present invention has been described with respect to several embodiments. However, the present invention is not limited to such an embodiment, and various modifications can be made. In addition, although it has been described that an SOI substrate is used for manufacturing, the present invention is not limited to this. The manufacturing method described with reference to FIGS. 2-1 to 2-2 is merely an example, and various manufacturing methods can be used for manufacturing the optical scanning device according to the present invention.

It is explanatory drawing of the optical scanning device which concerns on the 1st Embodiment of this invention. It is process explanatory drawing for demonstrating an example of the manufacturing method of the optical scanning device concerning the 1st Embodiment of this invention. It is process explanatory drawing for demonstrating an example of the manufacturing method of the optical scanning device concerning the 1st Embodiment of this invention. It is a schematic plan view which shows the modification of an electrode shape. It is explanatory drawing of the optical scanning device which concerns on the 2nd Embodiment of this invention. It is explanatory drawing of the optical scanning device which concerns on the 3rd Embodiment of this invention. It is explanatory drawing of the optical scanning device which concerns on the 4th Embodiment of this invention. It is explanatory drawing of the optical scanning device which concerns on the 5th Embodiment of this invention. It is explanatory drawing of the optical scanning device which concerns on the 6th Embodiment of this invention. 10 is a plan view of an optical scanning device described in Patent Document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Frame 2 Torsion beam 3 Mirror mass part 4 Cantilever 4a Spring part 4b Elastic deformation part 5 Electrode 6 Electrode 7 Separation groove 8 Piezoelectric element 14 Cantilever 18 Piezoelectric element

Claims (5)

An optical scanning device in which a mirror member supported by a pair of torsion beams reciprocally vibrates with the pair of torsion beams as a torsion rotation axis,
The fulcrum end of the torsion beam is fixed to a fixing member,
The non-fixed side ends of a pair of cantilevers that are symmetrically positioned with respect to the torsion beam are coupled to the same portion of the torsion beams, and the fixed side ends of the pair of cantilevers are fixed at positions symmetrical to the torsion beam. Fixed to
A piezoelectric element for generating a driving torque for the mirror member by deforming the cantilever is formed on the cantilever,
The cantilever is formed with a spring portion in the vicinity of the fixed side end thereof,
A first electrode and a second electrode facing each other for generating a force for pulling the cantilever toward its fixed side end are formed on the spring portion and the fixing member of the cantilever, respectively.
The resonance frequency of the mirror member can be adjusted by adjusting the applied voltage between the opposed first and second electrodes ,
An optical scanning device, wherein the cantilever is formed on a first silicon substrate side of an SOI substrate, and the torsion beam and the mirror member are formed on a second silicon substrate side of the SOI substrate. An optical scanning device in which a mirror member supported by a pair of torsion beams reciprocally vibrates with the pair of torsion beams as a torsion rotation axis,
The fulcrum end of the torsion beam is fixed to a fixing member,
The non-fixed side ends of a pair of cantilevers that are symmetrically positioned with respect to the torsion beam are coupled to the same portion of the torsion beams, and the fixed side ends of the pair of cantilevers are fixed at positions symmetrical to the torsion beam. Fixed to
A first piezoelectric element for generating a driving torque for the mirror member by deforming the cantilever is formed on the cantilever,
The cantilever is formed with a spring portion in the vicinity of the fixed side end thereof,
A second piezoelectric element for generating a force for pulling the cantilever to its fixed side end by deforming the spring portion of the cantilever is formed in the spring portion of the cantilever,
The resonance frequency of the mirror member can be adjusted by adjusting the applied voltage of the second piezoelectric element ,
An optical scanning device, wherein the cantilever is formed on a first silicon substrate side of an SOI substrate, and the torsion beam and the mirror member are formed on a second silicon substrate side of the SOI substrate. An optical scanning device in which a mirror member supported by a pair of torsion beams reciprocally vibrates with the pair of torsion beams as a torsion rotation axis,
The fulcrum end of the torsion beam is fixed to a fixing member,
The non-fixed side ends of the pair of first cantilevers that are symmetrically positioned with respect to the torsion beam are coupled to the same portion of the torsion beam, and the fixed side ends of the pair of first cantilevers are symmetrical with respect to the torsion beam. Fixed to the fixing member at the position,
The non-fixed side ends of the pair of second cantilevers that are symmetrically positioned with respect to the torsion beam are coupled to the same portion of the torsion beam, and the fixed side ends of the pair of second cantilevers are symmetrical with respect to the torsion beam. Fixed to the fixing member at the position,
A piezoelectric element for generating a driving torque for the mirror member by deforming the first cantilever is formed on the first cantilever,
The second cantilever is formed with a spring portion in the vicinity of its fixed side end,
A first electrode and a second electrode facing each other for generating a force for pulling the second cantilever to its fixed side end are respectively formed on the spring part and the fixing member of the second cantilever,
The resonance frequency of the mirror member can be adjusted by adjusting the applied voltage between the opposed first and second electrodes ,
The light, wherein the first cantilever and the second cantilever are formed on the first silicon substrate side of the SOI substrate, and the torsion beam and the mirror member are formed on the second silicon substrate side of the SOI substrate. Scanning device. An optical scanning device in which a mirror member supported by a pair of torsion beams reciprocally vibrates with the pair of torsion beams as a torsion rotation axis,
The fulcrum end of the torsion beam is fixed to a fixing member,
The non-fixed side ends of the pair of first cantilevers that are symmetrically positioned with respect to the torsion beam are coupled to the same portion of the torsion beam, and the fixed side ends of the pair of first cantilevers are symmetrical with respect to the torsion beam. Fixed to the fixing member at the position,
The non-fixed side ends of the pair of second cantilevers that are symmetrically positioned with respect to the torsion beam are coupled to the same portion of the torsion beam, and the fixed side ends of the pair of second cantilevers are symmetrical with respect to the torsion beam. Fixed to the fixing member at the position,
A first piezoelectric element for generating a driving torque for the mirror member by deforming the first cantilever is formed on the first cantilever,
The second cantilever is formed with a spring portion in the vicinity of its fixed side end,
A second piezoelectric element for generating a force for pulling the second cantilever to its fixed side end by deforming the spring portion of the second cantilever is formed in the spring portion of the second cantilever;
The resonance frequency of the mirror member can be adjusted by adjusting the applied voltage of the second piezoelectric element ,
The light, wherein the first cantilever and the second cantilever are formed on the first silicon substrate side of the SOI substrate, and the torsion beam and the mirror member are formed on the second silicon substrate side of the SOI substrate. Scanning device.   4. The optical scanning device according to claim 1, wherein the first and second electrodes are comb-like electrodes.

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