JP2011128244A - Oscillation element, optical scanner, image projector and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oscillation element in which the freedom degree of design can be remarkably improved while a desired oscillation characteristic is secured; and to provide an optical scanner, an image projector and an image forming apparatus. <P>SOLUTION: The oscillation element 30 includes: an oscillation part (beam part 31) on which an optical mirror part 322 is provided; and a driving part (magnetic field imposing means 70 or the like) which oscillates the oscillation part; wherein the oscillation part has an oscillation characteristic in which the peak form of the oscillation characteristic curve, which shows the relation between the variation in an resonance frequency and the magnitude of a distortion amplitude, is line symmetry, the freedom degree of design can be remarkably improved while a desired oscillation characteristic is assured. Further, components involved in driving together with the oscillation element 30 are made to be compact, thus the performance of an actuator device 1, an optical scanner, an image projector and an image forming apparatus or the like can be improved. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vibration element, an optical scanning device, a video projection device, and an image forming device, for example.

  Conventionally, for example, an optical scanning device such as an optical scanner is known as an example of a device including a vibration element (see, for example, Patent Document 1). In the optical scanning device described in Patent Document 1, a torsion beam portion made of stainless steel is provided on a substrate, a plate wave is induced on the substrate by a piezoelectric body or the like, and a mirror portion supported by the torsion beam portion is swung. It has become.

JP 2006-293116 A

  By the way, when mounting a vibration element on an electronic device such as a conventional optical scanning device, if the vibration element cannot be mounted as it is, the vibration element can be reduced in size, the element structure can be reviewed, or the dimensions can be changed. There is a need to. In the optical scanning device described in Patent Document 1 described above, since the torsion beam portion is formed of stainless steel, when the design change of the vibration element (for example, the dimension change of the torsion beam portion) is performed as described above, There is a risk that the vibration becomes unstable and a desired vibration characteristic cannot be obtained, and the device performance is deteriorated.

  For example, in order to reduce the size of the optical scanning device, it is necessary to improve the vibration element, in particular, to reduce the size of the element structure and the drive unit that controls the vibration. Drive efficiency is required. If the torsion beam is shortened to reduce the size of the vibration element, the non-linearity of the spring becomes stronger with the increase of the stress in the torsion beam, the asymmetry of the frequency characteristic increases, and the vibration near the resonance frequency becomes unstable. There is a problem of becoming. In this case, it is possible to avoid the vicinity of the resonance frequency, but eventually the drive efficiency is lowered, so that it is difficult to reduce the size of the vibration element. The asymmetry appearing in this frequency characteristic is greatly affected by the vibration damping rate, and when the non-linearity of the spring is the same and only the vibration damping rate is reduced, the asymmetry changes in the increasing direction. For this reason, in order to avoid the phenomenon that the vibration in the vicinity of the resonance frequency becomes unstable and to realize the miniaturization, it is necessary to reduce both the nonlinearity of the spring and the vibration damping rate.

  For example, when the vibration element is downsized while maintaining the resonance frequency and the torsion angle, if the torsion beam is shortened, the stress applied to the torsion beam portion is increased. For this reason, in the case where the twisted needle portion made of stainless steel is shortened, the fatigue characteristics are deteriorated, and the problem of a decrease in driving efficiency due to an increase in the vibration damping rate occurs. On the other hand, in order to reduce the vibration damping rate and improve the fatigue characteristics, it is conceivable to use precipitation hardening stainless steel or the like for the torsion beam part. However, in order to cope with the downsizing, further improvement of the vibration characteristics is required.

  Note that the vibration attenuation rate fluctuates due to the influence of the damping property of the material forming the torsion beam portion, the air resistance of the mirror, and the like. Therefore, it is difficult to reduce the size of the vibration element by simply using a material having low vibration damping properties without considering nonlinearity. Further, when the air resistance is reduced by devising the shape of the mirror or reducing the pressure in order to reduce jitter, the nonlinearity appears strongly, so that it is difficult to reduce the size of the vibration element.

  In any case, since the above-mentioned various problems occur in the vibration element mounted on the conventional optical scanning device or the like, at present, it is effective to provide the freedom of design of the vibration element while ensuring the desired vibration characteristics. No means has been proposed.

  The above-described problem is the same when improving the performance of various optical devices including a vibrating element, such as an optical scanning device, a video projection device, and an image forming device.

  SUMMARY OF THE INVENTION In view of the circumstances described above, an object of the present invention is to provide a vibration element, an optical scanning device, a video projection device, and an image forming device that can significantly improve the degree of design freedom while ensuring desired vibration characteristics. To do.

  The vibration element of the present invention that achieves the above object includes a vibration part having a vibration characteristic in which a peak shape of a resonance characteristic curve indicating a relationship between a change amount of a resonance frequency and a magnitude of a distortion amplitude is line symmetric, and the vibration part. And a drive unit that vibrates.

  Further, another vibration element of the present invention that achieves the above object includes a vibration part having a vibration characteristic in which a peak shape of a resonance characteristic curve showing a relationship between a change amount of a resonance frequency and a magnitude of a distortion amplitude is line symmetric, A drive unit that vibrates the vibration unit and a decompression space forming unit that forms a decompression space in which at least a part of the vibration unit is disposed are provided.

  Furthermore, another vibration element of the present invention that achieves the above object includes a vibration part having a vibration characteristic in which a peak shape of a resonance characteristic curve showing a relationship between a change amount of a resonance frequency and a magnitude of a distortion amplitude is line symmetric, It is provided with the optical mirror part provided in the said vibration part, and the drive part which vibrates the said vibration part.

  Further, another vibration element of the present invention that achieves the above object includes a vibration part having a vibration characteristic in which a peak shape of a resonance characteristic curve showing a relationship between a change amount of a resonance frequency and a magnitude of a distortion amplitude is line symmetric, An optical mirror unit provided in the vibration unit, a drive unit that vibrates the vibration unit, and a decompression space forming unit that forms a decompression space in which at least a part of the vibration unit is disposed. To do.

  Further, an optical scanning device of the present invention that achieves the above object includes a vibrating section having a vibration characteristic in which a peak shape of a resonance characteristic curve showing a relationship between a change amount of a resonance frequency and a magnitude of a distortion amplitude is axisymmetric, An optical mirror unit provided in the vibration unit, a drive unit that vibrates the vibration unit, and a light source that irradiates light to the mirror surface of the optical mirror unit, and light based on the vibration of the optical mirror unit by the vibration unit It is characterized by scanning.

  Furthermore, an image projection apparatus of the present invention that achieves the above object includes a vibration unit having a vibration characteristic in which a peak shape of a resonance characteristic curve showing a relationship between a change amount of a resonance frequency and a magnitude of a distortion amplitude is axisymmetric, An optical mirror unit provided in the vibration unit, a drive unit that vibrates the vibration unit, and a light source that irradiates light to the mirror surface of the optical mirror unit, and light based on the vibration of the optical mirror unit by the vibration unit It scans and projects an image.

  Furthermore, an image forming apparatus of the present invention that achieves the above object includes a vibration unit having a vibration characteristic in which a peak shape of a resonance characteristic curve showing a relationship between a change amount of a resonance frequency and a magnitude of a distortion amplitude is line symmetric, An optical mirror unit provided in the vibration unit, a drive unit that vibrates the vibration unit, and a light source that irradiates light to the mirror surface of the optical mirror unit, and light based on the vibration of the optical mirror unit by the vibration unit An image is formed by scanning.

  The present invention has an effect that it is possible to realize a vibration element, an optical scanning device, a video projection device, and an image forming device that can remarkably improve design freedom while ensuring desired vibration characteristics.

Schematic which shows an example of the actuator apparatus provided with the vibration element of Embodiment 1. FIG. Schematic which shows an example of the drive means connected to the actuator apparatus of Embodiment 1. FIG. The figure which shows the resonance characteristic curve which shows the relationship between the variation | change_quantity of a resonant frequency, and the magnitude | size of a distortion amplitude. The figure which shows the twist amplitude dependence of a vibration damping factor. The figure which shows the influence which the vibration damping factor of material and the nonlinearity of a spring characteristic have on the frequency characteristic of a vibration element. The figure which showed the vibration damping factor and nonlinearity of the vibration element together. The figure which shows the relationship between the change rate of an allowable distortion amplitude, and the change rate of the length of a torsion beam. The schematic plan view which shows the shape modification of a mirror. The figure which shows the characteristic data of a vibration element. FIG. 6 is a schematic cross-sectional view illustrating an example of an actuator device including the vibration element according to the second embodiment. FIG. 6 is a schematic diagram illustrating an example of an actuator device including a vibration element according to a third embodiment. Schematic which shows an example of the actuator apparatus provided with the vibration element which concerns on Embodiment 4. FIG. FIG. 6 is a schematic diagram of an image forming apparatus including a vibration element according to a fifth embodiment. FIG. 7 is a schematic diagram of a video projection device including a vibration element according to a sixth embodiment.

  Hereinafter, the present invention will be described in detail based on embodiments.

  The vibration element of the present invention includes a vibration part and a drive part that vibrates the vibration part, and the vibration part is symmetrical with respect to the peak shape of the resonance characteristic curve indicating the relationship between the amount of change in the resonance frequency and the magnitude of the distortion amplitude. The characteristic is that it has vibration characteristics.

  Here, the vibration element of the present invention has a vibration characteristic in which the resonance characteristic curve is axisymmetric and has a very steep peak shape, that is, exhibits a vibration characteristic in which the nonlinearity of the spring characteristic is very small. In particular, the vibration element according to the present invention exhibits high vibration characteristics under a reduced pressure environment so that non-linearity is small enough not to cause vibration instability even when the resonance characteristics become sharp. And according to such a vibration element of this invention, since a high vibration characteristic is obtained, the freedom degree of design can be improved significantly, ensuring a desired vibration characteristic.

  In addition, since the vibration element of the present invention can significantly improve the vibration characteristics as compared with the vibration element having the same size and structure as compared with the related art, for example, the vibration element of the present invention is applied to an electronic device such as an optical scanning device. In mounting, it is possible to provide a degree of freedom in designing to reduce the size of the vibration element, or to review the element structure or change dimensions. Thereby, according to the vibration element of this invention, various small-sized electronic devices are realizable, maintaining device performance.

  Furthermore, the vibration element of the present invention having the above-described high vibration characteristics is, for example, a material whose Young's modulus after processing is lowered by work hardening treatment, and whose Young's modulus is recovered or raised by subsequent age hardening treatment, Can be realized by forming the vibration part with a metal material such as work-hardening and age-hardening type Co—Ni-based alloy.

  Specifically, it is made of a material that temporarily lowers the Young's modulus of the base material (work object) by work hardening treatment, and recovers or increases the Young's modulus of the base material by subsequent age hardening treatment. It is preferable to form a vibration part. More specifically, as a material for forming the vibration part, for example, it is a material that has been work-hardened by applying strong processing at room temperature, and then age-hardened by strain aging heat treatment. Dislocations are introduced at a high density to such an extent that the Young's modulus is lowered by plastic working, and the material is formed by a material whose dislocation motion is inhibited by the subsequent age hardening until the Young's modulus is recovered or increased. In the present invention, “recovering or increasing Young's modulus by age hardening treatment” means, for example, increasing from Young's modulus before work hardening treatment, or raising the Young's modulus before work hardening treatment to the same level or higher. Including. Further, in the present invention, “reducing Young's modulus by work hardening treatment” includes, for example, lowering the Young's modulus to such an extent that it can be recovered or raised by subsequent age hardening treatment.

  Here, the “work-hardening and age-hardening type Co—Ni-based alloy” refers to, for example, a Co—Ni-based alloy that has been effectively subjected to work-hardening treatment and age-hardening treatment. The vibration part is formed, for example, by subjecting the material (starting raw material) to be work-hardened and age-hardened Co—Ni-based alloy to work-hardening treatment and then performing age-hardening treatment.

  Specifically, work hardening is performed by cold rolling from a starting material containing a substitutional solute element in a matrix containing at least Co and Ni obtained through steps such as hot forging and homogenization heat treatment after melting. After processing, if necessary, for example, by processing into a predetermined shape by molding such as press processing, laser processing, wire cutting, etc., and then performing age hardening heat treatment in vacuum or reducing atmosphere, It is possible to obtain a vibration part that effectively exhibits good vibration characteristics such as strength, low damping ability, and high elastic limit.

  Here, the material forming the vibration part is preferably a material having a face-centered cubic lattice structure with a low stacking fault energy, and the “Suzuki effect” is effective in which solute elements segregate in the stacking fault and fix the extended dislocation. It is preferable that it can be utilized. As a result, the width of the extended dislocation is expanded, and it becomes possible to promote the Suzuki effect and firmly fix the extended dislocation at the time of work hardening and age hardening. This Suzuki effect is a fixing mechanism that works effectively even at high temperatures, and is particularly effective during aging heat treatment. In addition to this, a Cottrell effect segregating in the dislocation center and a dislocation slip inhibiting mechanism due to the formation of fine transformation twins may be used together.

  With such materials, it is possible to introduce high-density dislocations with strong processing, and the strength and durability are greatly improved by work hardening, but at this stage there are still overhangs of dislocations, so the Young's modulus Will decline. In other words, work hardening is performed by introducing strain to the extent that the Young's modulus decreases. Thereafter, by firmly fixing dislocations by aging heat treatment, the strength and durability can be further improved, and the Young's modulus can be increased or recovered, or further increased before work hardening. In this way, when the dislocations are firmly fixed to such an extent that the Young's modulus increases or recovers, or increases more than before work hardening, the internal friction due to the vibration of the dislocation lines is reduced and the Q value of the vibration element is greatly improved. Furthermore, the elastic limit is improved by increasing the yield point and reducing the internal friction due to the strength improvement, and the linear elastic region on the stress-strain diagram is expanded, that is, the linearity of the spring characteristics is improved.

  In a material having a face-centered cubic lattice structure, the Young's modulus depends on the interatomic distance, and the <110> orientation is the maximum, the <111> orientation is the minimum, and the <100> orientation is the middle. When crystal orientation is achieved by cold rolling, the Young's modulus has anisotropy, and the direction in which the <110> texture is formed is maximized. Although not particularly limited, considering the strength against bending, it is preferable to use a material in the direction in which the <110> texture having a large Young's modulus is formed in the vibration part, and the age hardening treatment also has a Young's modulus in this direction. Is preferably applied so as to recover or rise.

  Moreover, you may form in a vibration part using the wire which gave the work hardening by cold drawing. Further, it is also possible to use a material in which the cold-drawn wire rod is cold-rolled to control the formation of the texture.

  Here, as a forming method, superplastic processing may be used. In addition, the age hardening treatment is preferably performed based on a temperature condition that allows age hardening to proceed effectively, for example, a temperature condition that is appropriately adjusted according to the processing conditions of the work hardening treatment, although depending on the processing conditions. The treatment can be carried out by treating for several tens of minutes to several hours under an environment of recrystallization temperature or lower, for example, about 400 to 700 ° C. Moreover, in such a heat treatment, for example, the Suzuki effect may be promoted by performing it in a strong magnetic field environment of 1T or more to shorten the treatment time.

  Then, according to the present invention, as described above, by forming the vibration part having the vibration characteristic in which the peak shape of the resonance characteristic curve indicating the relationship between the amount of change in the resonance frequency and the magnitude of the distortion amplitude is line symmetric, In addition to enhancing fatigue characteristics and mechanical properties, the vibration damping rate is very low, and in particular, the nonlinearity of the spring is so small that it does not cause instability with respect to the low vibration damping rate. Also, the distortion amplitude dependence is very small. Therefore, it is advantageous in that the vibration element having desired fatigue characteristics and vibration characteristics and the actuator device including the vibration element can be reduced in size and the power consumption can be reduced.

Specifically, in order to obtain a characteristic in which the peak shape of the resonance characteristic curve indicating the relationship between the amount of change in the resonance frequency and the magnitude of the distortion amplitude is axisymmetric, that is, a characteristic in which the nonlinearity of the spring characteristic is very small. For example, the vibration part constituting the strain deformation part of the vibration element is formed of the above-described work hardening and age hardening type Co-Ni based alloy, and has high strength, a wide linear elastic region, and internal friction. The characteristic is such that the peak shape of the resonance characteristic curve showing the relationship between the amount of change in the resonance frequency and the magnitude of the distortion amplitude is sharp and line symmetric, that is, the Q value is high, and A characteristic in which the nonlinearity of the spring characteristic is very small can be obtained. Such a vibration part does not cause instability even when the maximum strain amplitude due to vibration deformation increases to about 3 × 10 ⁻³ , and a vibration element with low power consumption can be obtained. On the other hand, since the vibration unit has a Q value indicating ease of vibration of 1000 or more, the vibration damping rate is very small, and the non-linearity of the spring characteristics is small. As a result, the power consumption can be greatly reduced while improving the vibration characteristics. Therefore, the present invention provides a vibration element, an optical scanning device, a video projection device, and an image forming apparatus that can obtain desired fatigue characteristics and can significantly improve the degree of design freedom while ensuring desired vibration characteristics. Can be realized.

  The above-mentioned “Co—Ni-based alloy” is an alloy containing cobalt [Co] and nickel [Ni]. Preferably, chromium [Cr] which reduces stacking fault energy and solid solution strengthening of the matrix In addition, molybdenum [Mo], iron [Fe] and the like are included as solute elements that fix dislocations by segregation and contribute to the improvement of aging and work hardening ability, for example, Co—Ni—Cr—Mo alloy, Co—Ni -Fe-Cr alloy etc. are good. In addition, these alloys include niobium [Nb] that functions similarly as a solute element, manganese [Mn] that stabilizes the face-centered cubic lattice phase and decreases stacking fault energy, matrix strengthening and stacking fault energy. Tungsten [W] that contributes to lowering, titanium [Ti] that contributes to refinement of the ingot structure and strength improvement, boron [B] that improves hot workability, magnesium [Mg], etc. are dissolved in the matrix. , Cr, Mo, Nb, etc., and carbon [C] that forms carbides and strengthens the grain boundaries may be contained.

  Here, as a Co-Ni-Cr-Mo alloy, the main composition is Co20.0-50.0% by weight ratio, Ni20.0-45.0%, Cr + Mo20.0-40.0% (Cr: 18 to 26%, Mo: 3 to 11%), particularly Co 31.0 to 37.3%, Ni 31.4 to 33.4%, Cr 19.5 to 20.5%, Mo 9.5 More preferably, the content is set to ˜10.5%. By forming the vibration part from the Co—Ni—Cr—Mo alloy having such a composition, it is very advantageous for downsizing the vibration element and the like. In such an alloy, a <100> texture is formed in the rolling direction, and a <110> texture is formed in a direction orthogonal to the rolling direction. Therefore, a material in a direction orthogonal to the rolling direction is used for the vibration part. Is preferred. Further, it is optimal that the aging heat treatment with such an alloy is performed at a temperature of 500 ° C. to 600 ° C. for about 2 hours.

  In the present invention, the vibration part is preferably formed from a work-hardening and age-hardening type Co—Ni based alloy exhibiting non-magnetism, for example, a Co—Ni—Cr—Mo alloy having the above composition. This is because stable electromagnetic driving can be realized when, for example, a magnetic field applying unit is used as the unit (driving unit) for vibrating the vibrating unit. Note that the driving unit is not limited to the magnetic field applying unit, and for example, a piezoelectric element or the like may be adopted, and in this case, the magnetism of the material does not matter.

  In the present invention, it is preferable to dispose at least a part of the vibration element from the work-hardening and age-hardening type Co—Ni-based alloy in a reduced-pressure space forming part (sealing structure) that forms a reduced-pressure space. This is because the vibration characteristics can be further enhanced as compared with normal pressure. In particular, when various functional parts, specifically optical mirrors or the like are provided in the vibration part to form a high-function device, at least a part of the above-described vibration part, that is, the functional part or the like is disposed in the decompression space forming part. More preferably. Thereby, the influence of the air resistance concerning a functional part etc. can be reduced and a vibration characteristic can be improved further. In this invention, you may make it cover the whole structures, such as a vibration part and a function part, by a decompression space formation part.

  In the present invention, as described above, it is preferable to form the vibration part using work-hardening and age-hardening type Co—Ni-based alloy, but the present invention is not particularly limited thereto. It is preferable to use any material that lowers the Young's modulus and increases the Young's modulus by subsequent age hardening treatment, recovers to the same level after work hardening treatment, or rises and rises after work hardening treatment. it can.

Hereinafter, specific examples of an actuator device, an optical scanning device, and an image projection device having the vibration element of the present invention will be described in detail with reference to the drawings based on the embodiments.
(Embodiment 1)

  1A and 1B are schematic views illustrating an example of an actuator device including a vibration element according to Embodiment 1 of the present invention. FIG. 1A is a schematic top view, and FIG. 1B is a cross-sectional view taken along line AA ′. It is. FIG. 2 is a schematic view showing an example of drive means connected to the actuator device of FIG.

  As shown in FIGS. 1A and 1B, the actuator device 1 according to the present embodiment is a vibrating mirror device, and includes a substrate 10, a holding member 20 on which the substrate 10 is mounted, and a vibration element. 30. In this embodiment, the holding member 20 is provided with an annular flange portion 21 along the peripheral edge of the substrate 10 as shown in FIGS. 22 is constituted. In the present embodiment, the vibration element 30 is mounted in the recess 22 and is disposed in the decompression space 50 configured (partitioned) by the substrate 10, the holding member 20, and the cover member 40.

  In addition, in this embodiment, for example, the vibration element 30 includes a frame (outer frame portion) 60 that serves as a joint portion with the holding member 20, and the opposite end portions of the frame 60 at the concave portion (opening) 22 of the holding member 20. And a mass body (functional part) 32 provided at a central portion in the longitudinal direction of the beam portion 31, that is, a portion corresponding to the opening center of the holding member 20. A magnetic field applying unit 70 is provided on the substrate 10 at a portion facing the mass body 32.

  Here, the beam portion 31 constituting the deformed portion of the vibration element 30 is made of a material whose Young's modulus after processing is reduced by work hardening processing and whose Young's modulus is increased by subsequent age hardening processing, for example, In this embodiment, it is formed from a work-hardening and age-hardening type Co—Ni based alloy exhibiting non-magnetism. Examples of such non-magnetic work-hardening and age-hardening type Co—Ni based alloys include, for example, Co-Ni—Cr—Mo alloys of SPRON510 (trade name: SPRON [registered trademark] manufactured by Seiko Instruments Inc.) Can be used. It should be noted that such a material such as SPRON 510 has a high vibration characteristic such as a characteristic of a low damping capacity by forming the beam portion 31 by performing a heat treatment after increasing the strength by a strong process such as rolling, for example. The vibration element 30 can be obtained.

  Moreover, the beam part 31 can be processed into a predetermined shape by, for example, pressing, laser processing, wire cutting, or the like. Here, as a processing method, for example, superplastic processing may be used. The beam portion 31 may be formed by joining a nonmagnetic work-hardening and age-hardening Co—Ni-based alloy wire to the frame 60. The beam portion 31 formed in this way can be obtained, for example, by performing a heat treatment as an age hardening treatment for improving vibration characteristics after the processing effect treatment described above. The heat treatment to the beam portion 31 here is preferably performed at a temperature of 400 to 700 ° C. for several tens of minutes to several hours. However, in order to shorten the processing time, for example, heat treatment in a strong magnetic field is used. Is also possible.

  For example, in this embodiment, a plate-like member (not shown) is produced by performing a work hardening treatment by rolling or the like using a material (starting material) that becomes a work hardening and age hardening type Co—Ni base alloy, The beam part 31 was formed by performing an age hardening process after processing a plate-shaped member into a predetermined shape. Here, in the work hardening process and the age hardening process when producing the plate-like member, the <100> crystal orientation is oriented in the rolling direction, and the <110> crystal orientation is within the plate-like member plane. The crystal orientation was performed so as to be in a direction orthogonal to the rolling direction, and the Young's modulus was increased in the direction orthogonal to the rolling direction.

  Note that a mirror installation part 311 for installing an optical mirror part 322 described later is provided at a substantially central part of the beam part 31 so as to be wider than the beam part 31. In the present embodiment, the mirror installation portion 311 is provided integrally with the beam portion 31 and is formed simultaneously with the shape processing as the beam portion 31.

  Further, as shown in FIG. 1B, the mass body 32 provided in such a beam part 31 includes an optical mirror part 322 installed in the mirror installation part 311 and a back surface of the mirror arrangement part 311, that is, optical It is comprised from the magnet 323 provided in the surface on the opposite side to the mirror part 322. FIG.

  Here, the optical mirror part 322 and the mirror arrangement part 311 have an outer shape larger than the width dimension of the beam part 31. For example, in this embodiment, the optical mirror part 322 and the mirror arrangement part 311 are plate-like and have an outer shape. Is a rectangle. Further, the magnet 323 is provided so as to reach both ends over the longitudinal direction of the mirror arrangement portion 311. Further, in the present embodiment, the magnet 323 is provided such that the NS direction is parallel to the horizontal direction, that is, the surface direction of the substrate 10. On the other hand, the magnetic field applying means 70 on the substrate 10 is made of a coiled metal pattern and is provided in a region facing the mass body.

  Further, the optical mirror unit 322 may be a reflective film such as Al or Au formed by vapor deposition or the like, or a member formed by bonding or bonding a mirror-formed member such as a silicon wafer. However, it is not particularly limited.

  On the other hand, the type of magnet 323 is required to be as small as possible, contribute little to the weight of the vibration element 30, and have a sufficient magnetic force. Therefore, an Nd—Fe—B magnet or an Sm—Co magnet is required. Etc. can be suitably used. Moreover, the form of the magnet 323 may be, for example, a thin film magnet formed by a sputtering method or the like in addition to a sintered magnet or a bonded magnet, and is not particularly limited.

  And the magnetic field application means 70 which makes a magnetic field act on such a magnet 323 will not be specifically limited if the torque which can excite a torsional vibration to the vibration element 30 is added to a magnet, For example, Fig.1 (a) In addition to such a sheet coil, a coil or the like including a soft magnetic material serving as a yoke may be used. In addition, the magnetic field applying means 70 may be provided on both sides so as to sandwich the vibration element 30 within a range where the optical mirror portion 322 is not hidden.

  Note that the magnetic field applying unit 70 is not particularly limited as long as the driving circuit 75 is connected as shown in FIG. 2 constituting a part of the driving unit and can output a signal including a frequency near the resonance frequency of the vibration element 30. For example, a triangular wave or a pulse output may be used in addition to the sine wave.

  In the actuator device 1 according to the present embodiment having such a structure, the magnet 323 receives a rotational force by the magnetic field from the magnetic field applying means 70 driven by the drive circuit 75, and the vibration composed of the mass body 32 and the beam portion 31. Torsional vibration is excited in the element 30. Specifically, when a magnetic field is generated by the magnetic field applying means 70, the magnet 323 receives the action of the magnetic field, whereby a rotational force is applied to the mass body 32, and the beam portion 31 is twisted and deformed in conjunction with this. Then, by repeatedly operating such torsional deformation of the beam portion 31 under the control of the drive circuit 75, the optical mirror portion 322 becomes a vibrating mirror (functional portion) that operates one-dimensionally.

  In the present embodiment, as described above, the beam portion 31 to be twisted and deformed is made of work-hardened and age-hardened Co—Ni-based alloy. Characteristics and the like can be greatly improved. In addition, the vibration element 30 has a very low vibration damping rate. In particular, the non-linearity of the spring is so small that instability is not generated with respect to the low vibration damping rate, and the strain amplitude dependency of the vibration damping rate is also very high. A small vibration element 30 is obtained.

  For this reason, according to this embodiment, size reduction of the vibration element 30 can be achieved by shortening the beam portion 31 while ensuring desired fatigue characteristics and vibration characteristics. In addition, by applying the vibration element 30 thus downsized to a device structure such as a MEMS (Micro Electro-Mechanical Systems) mirror or an optical switch, it is possible to reduce the size together with components related to driving. In addition to contributing to the overall size reduction, desired vibration characteristics can be obtained, so that a highly functional device with low power consumption can be realized. In particular, in the present embodiment, the vibration characteristics can be further enhanced as compared with normal pressure by disposing the vibration element 30 made of the above-described work hardening and age hardening type Co—Ni based alloy in the reduced pressure space 50. In addition, it is possible to reduce the influence of air resistance on the functional part and the like, which contributes to improvement of functionality.

  Here, in the vibration element 30 applied to the actuator device 1 of the present embodiment, the beam portion 31 constituting the main portion of the vibration portion is made of work-hardening and age-hardening type Co—Ni based alloy, thereby resonating. A characteristic in which the peak shape of the resonance characteristic curve showing the relationship between the amount of change in frequency and the magnitude of the distortion amplitude is line symmetric, that is, a vibration characteristic with very small nonlinearity of the spring characteristic is obtained.

FIG. 3 shows the amount of change in the resonance frequency for the vibration element of Example 1 and the vibration elements of Comparative Examples 1 to 3 manufactured based on the structure of the vibration element 30 according to Embodiment 1 described above (FIG. 1). The resonance characteristic curve (frequency characteristic) which shows the relationship with the magnitude | size of distortion amplitude is shown. The horizontal axis is the normalized angular frequency ω / ω ₀ , and the vertical axis is the torsion amplitude magnitude θ (deg). As the value of ω ₀ , an angular frequency (extrapolated) value when the torsional amplitude is zero is used.
[Example 1]

Using a rolled material of SPRON 510 having a composition of 35% Co, 32% Ni, 20% Cr, 10% Mo as work hardening and age hardening type Co—Ni base alloy, heat treatment at 550 ° C. for 2 hours is performed as aging treatment. A resonator element according to Example 1 having a vibrating portion formed by applying the same was used. Note that the resonance frequency of the resonator element of Example 1 was about 2 kHz.
[Comparative Example 1]

Among the same austenitic stainless steels as SUS304, those having the same structure as in Example 1 were prepared except that the vibration part was made of SUS301 having good mechanical properties, and this was used as the vibration element of Comparative Example 1.
[Comparative Example 2]

A vibrating element of Comparative Example 2 was prepared by preparing a vibrating part having the same structure as that of Example 1 except that the vibrating part was made of precipitation hardening stainless steel SUS631.
[Comparative Example 3]

  A vibrating element of Comparative Example 3 was made having the same structure as that of Example 1 except that only work hardening was performed.

  As shown in FIG. 3, when the resonance frequency characteristics of Example 1 and Comparative Examples 1 to 3 are compared, the vibration element made of SUS301 and SUS631 of Comparative Examples 1 to 3 and a work-hardening-only Co—Ni based alloy is obtained. The vibration Q value is low, that is, the vibration damping rate is large, the resonance characteristics are asymmetric, and the nonlinearity of the spring characteristics appears.

  On the other hand, in the vibration element of Example 1, the characteristic that the peak shape of the resonance characteristic curve is axisymmetric in both cases of the atmospheric pressure environment and the reduced pressure environment, that is, the nonlinearity of the spring characteristic. However, very small vibration characteristics appear. In particular, the vibration element of Example 1 shows very high non-linearity in a reduced pressure environment despite the fact that it has very sharp characteristics and high vibration characteristics.

  As described above, the vibration element according to the first embodiment exhibits vibration characteristics with very small non-linearity of the spring characteristics, and high vibration characteristics can be obtained. Therefore, design freedom can be ensured while ensuring desired vibration characteristics. Can do. That is, the vibration element of Example 1 can significantly improve the vibration characteristics as compared with, for example, the case where the materials of Comparative Example 1 (SUS301) and Comparative Example 2 (SUS631) are used as the material of the vibration part. . For this reason, for example, when mounting the resonator element according to the first embodiment on an electronic device such as an optical scanning device, the design freedom to reduce the size of the resonator element, review the element structure, change the dimensions, or the like. The degree can be remarkably improved. Therefore, according to the resonator element of the first embodiment, various small electronic devices can be realized while maintaining the device performance.

FIG. 4 shows vibration damping of the Co—Ni based alloy that has been subjected to work hardening and age hardening treatment, and SUS301 and SUS631 used for the vibration elements of Comparative Examples 1 and 2 used in the vibration element of Example 1. The torsional amplitude dependence of the rate is shown. The torsional amplitude dependency varies depending on the cross-sectional shape and length of the beam. Therefore, the torsional amplitude θ is converted to the maximum strain amplitude γ corresponding to the maximum shear stress applied to the beam as a property of the material independent of the shape. It is. FIG. 4 shows the measurement results under reduced pressure at which the air resistance can be ignored, and shows the vibration damping rate (Q ⁻¹ ) of the material itself, that is, the damping characteristics.

  In SUS301 and SUS631, the vibration damping rate greatly increases as the distortion amplitude increases. For this reason, when a vibration element using SUS301 or SUS631 (Comparative Examples 1 and 2) is used in a region where the distortion amplitude is large, a large yoke is used for the magnetic field application means in order to obtain a driving force, It is necessary to increase the capacity of the battery, which makes it difficult to reduce the size of the drive unit. In addition, SUS631 shows better characteristics in terms of vibration attenuation rate than SUS301, but is still insufficient in a region where the distortion amplitude is large. On the other hand, in the vibration element using the Co—Ni base alloy subjected to work hardening and age hardening used in Example 1, the vibration attenuation factor of the material has no distortion amplitude dependence, and the distortion amplitude is large. A large driving force is not required even when used in the above.

FIG. 5 shows the influence of the vibration damping rate of the material and the nonlinearity of the spring characteristics on the frequency characteristics of the vibration element. The horizontal axis is the normalized frequency, and the vertical axis is the torsional amplitude. When the spring characteristic is non-linear, the resonance frequency at which the maximum amplitude is obtained changes with an increase in the vibration amplitude. In FIG. 5, the resonance frequency is lowered, and at the same time, the characteristics on the low frequency side become steep, and when the vibration amplitude further increases, hysteresis appears. When the frequency characteristics become steep, the vicinity of the resonance frequency becomes an unstable state that is difficult to control. When using a vibration element having such characteristics, it is necessary to avoid the resonance frequency and use a larger driving force for forced vibration in order to obtain a desired vibration amplitude. This hinders downsizing of the drive parts. The frequency characteristic becomes steep, the hysteresis begins to occur when the amount of change in resonance frequency (δω / ω _o) is the vibration amplitude A _r above the damping factor _{^{Q -1 = (δω / ω o}} ) of the vibration The vibration amplitude can be stably driven at the resonance frequency within the range of _Ar or less.

FIG. 6 is a diagram showing both the vibration attenuation factor and the nonlinearity of the vibration element. The horizontal axis represents the magnitude of the distortion amplitude, and the vertical axis represents the vibration attenuation rate Q ⁻¹ and the change amount (δω / ω _o ) of the resonance frequency representing the magnitude of the nonlinearity. FIG. 6 (a) shows the measurement result under atmospheric pressure, and FIG. 6 (b) shows that under reduced pressure. The characteristic shown in FIG. 6B is in a state where the air resistance is almost negligible, and becomes an intermediate characteristic between FIG. 6A and FIG. 6B according to the magnitude of the air resistance. As described with reference to FIG. 5, the intersection of the graph of the vibration attenuation rate and the amount of change in the resonance frequency is the limit allowable distortion amplitude that can be stably driven at the resonance frequency, and must be used at a distortion amplitude lower than that. The graph of the vibration attenuation rate under atmospheric pressure in FIG. 6A includes the influence of the air resistance of the mirror, and therefore varies depending on the size and shape of the mirror. The graph of FIG. 6A is a case where a 2 × 3 mm ² rectangular mirror is used. In the graph of FIG. 6A, it can be seen that there is no intersection in the characteristics of the vibration element of the Co—Ni based alloy, and the value of the allowable strain amplitude is very large. In the extrapolated value, the distortion amplitude at the intersection is 3 to 4 times that of SUS301 and SUS631.

FIG. 7 shows the relationship between the change rate of the allowable strain amplitude γ and the change rate of the length L of the torsion beam. In this graph, the length required to obtain the same resonance frequency and the same torsion amplitude is obtained with the same mirror shape, with the cross section of the torsion beam being circular or a rectangle having a constant aspect ratio. That is, when the allowable strain amplitude is γ ₀ and the length of the beam is L ₀ in a vibrating portion using a certain material, how much can be made to produce a vibrating portion of the same specification if a material having an allowable strain amplitude of γ is used? This is a ratio indicating whether the length L is necessary. From this graph, it can be seen that if the allowable strain amplitude is 3 to 4 times, the length of the torsion beam can be reduced to ¼ or less, and the vibrating mirror can be greatly reduced in size.

  In the graph of FIG. 6A, the allowable distortion amplitudes of SUS301 and SUS631 are approximately the same. This indicates that the vibration element using SUS631 can improve the driving efficiency by the amount of the vibration attenuation factor lower than that of the vibration element of SUS301, but the vibration element cannot be reduced in size. The non-linearity of SUS631 is less than that of SUS301 but is not so small as to improve the allowable distortion amplitude. To reduce the size of the actuator device (vibrating mirror device, etc.), the vibration attenuation rate and the non-linearity Both show that it is important to have optimal characteristics.

  In the characteristics under reduced pressure in FIG. 6B, the allowable strain amplitudes of SUS301 and SUS631 are lower than the characteristics under atmospheric pressure in FIG. This indicates that when the air resistance is reduced, it is necessary to increase the length of the torsion beam in order to operate stably at the resonance frequency. That is, when jitter is reduced by arrangement in a decompression space or by devising the shape of the optical mirror unit 322 as shown in FIGS. 8A to 8C, it is more difficult to reduce the size. Yes.

  On the other hand, although the allowable strain amplitude of the vibration element when using a Co—Ni based alloy that has been subjected to work hardening and age hardening treatment is also reduced, it is 40% or more higher than SUS301 and SUS631. The value is maintained. From the graph of FIG. 7, the length of the torsion beam can be reduced to about 60% of SUS301 and SUS631. In applications such as laser beam printers and laser projectors that require highly accurate beam scanning, countermeasures against jitter are indispensable. In these applications, the effect of miniaturization according to the present invention is very large.

  In FIG. 9, the characteristic data of each vibration element of Example 1 and Comparative Examples 1 and 2 are shown. The actual twist angle is also described in the allowable strain amplitude. The Q value is the reciprocal of the vibration attenuation rate, and describes the value when the torsional amplitude is 25 °. Similarly, the power consumption is a value when the twist amplitude is 25 °. The value of 25 ° of the torsional amplitude is an approximate allowable value under reduced pressure in Comparative Examples 1 and 2, and the characteristics of each vibration element are compared under the same conditions as long as the vibration near the resonance frequency does not become unstable. ing.

  When the vibration elements of Example 1 and Comparative Example 2 are compared in terms of power consumption, they are 1/5 or less under atmospheric pressure and 1/30 under reduced pressure. Compared with Comparative Example 2, Example 1 It can be seen that the power consumption can be greatly reduced. For this reason, it can be seen that the vibration element of Example 1 has greatly improved driving efficiency, and the actuator device can be downsized.

Further, the allowable strain amplitude of the vibration elements of Example 1 and Comparative Example 3 is larger than 3 × 10 ⁻³ , and it can be seen that the allowable distortion amplitude of the vibration elements of Comparative Examples 1 and 2 is superior. In addition, regarding the vibration element of Comparative Example 3, because the vibration part is formed only by work hardening processing, the Q value is small and the power consumption is large compared to the vibration element of Example 1, that is, the vibration damping factor. Is very high and driving efficiency is low, which is disadvantageous for downsizing.

  In miniaturizing the vibration element, in order to minimize the length of the torsion beam, the distortion amplitude may be increased to the allowable limit with respect to the required torsion amplitude. The Q value under reduced pressure in Comparative Examples 1 and 2 shown in FIG. 9 is a value when operated with a distortion amplitude almost at the limit of the allowable value, and is the minimum vibration regardless of the mirror shape and the torsional amplitude. This value is obtained when an element is manufactured. Since air resistance is added under atmospheric pressure, the value is lower than this value. That is, when a minimum vibration element is manufactured within a range in which vibration does not become unstable, the Q value in the materials of Comparative Examples 1 and 2 is about 550 to 740, and a Q value exceeding 1000 cannot be obtained.

  On the other hand, under the reduced pressure of the example, a Q value exceeding 4000 with the same size as Comparative Examples 1 and 2 was obtained. Moreover, since the allowable value of the distortion amplitude is large as described above, it is possible to reduce the size of the vibration element. However, as shown in FIG. There is almost no amplitude dependence, and the Q value does not change even if the distortion amplitude is increased by downsizing. That is, it is possible to simultaneously improve the Q value and reduce the size of the vibration element.

  In addition, as described above, it is possible to reduce the size under the atmospheric pressure of the embodiment, but the Q value decreases due to the influence of the air resistance according to the mirror shape, the torsional amplitude, and the like. However, a value exceeding 1400 is obtained at the same size as Comparative Examples 1 and 2 as shown in FIG. 9, which exceeds 1000, which cannot be obtained with the materials of Comparative Examples 1 and 2 according to the present invention. It shows that the Q value can be realized.

In addition, when the durability test was performed on the vibration element of Example 1 with a resonance frequency of 2 kHz and a twist amplitude of 40 ° and a value exceeding the allowable strain amplitude of SUS301 and SUS631, 4 × 10 ¹⁰ times or more (5000) It was found that durability of more than hours) can be obtained.

In addition, the characteristic data of the vibration element of Example 1 shown in FIG. 9 was obtained by producing each vibration element having the same shape as Comparative Examples 1 to 3 for comparison with Comparative Examples 1 to 3. It does not limit the characteristics of the present invention.
(Embodiment 2)

  FIG. 10 is a schematic cross-sectional view illustrating an example of an actuator device provided with the resonator element according to the second embodiment of the invention.

  As shown in FIG. 10, the actuator device 1A of the present embodiment is the same as that of the first embodiment described above except that the cover member for sealing the vibration element 30 is not provided and the vibration element 30 is open to the atmosphere. . In the present embodiment, the same components described in the above-described first embodiment are denoted by the same reference numerals, and redundant description is omitted.

Specifically, in the actuator device 1A of the present embodiment, the beam part 31 constituting the vibration part is open to the atmosphere, and is used in a normal pressure state. Further, the holding member 20A is provided with a through hole 21A in the center, leaving the peripheral edge thereof. Even in such an environment where there is an influence of air resistance, the beam portion 31 is made of a Co—Ni based alloy that has undergone work hardening and age hardening treatment, so that desired fatigue characteristics and vibration characteristics are ensured. However, the device is advantageous for downsizing. In the present embodiment, since the vibrating portion including the beam portion 31 is open to the atmosphere, the area of the portion having a large moving speed is reduced from the rotational center of torsional vibration in order to reduce the influence of air resistance. For example, it is preferable to adopt the shapes of the optical mirror part 322 and the beam part 31B as shown in FIGS. 8D to 8F.
(Embodiment 3)

  11A and 11B are schematic views illustrating an example of an actuator device including the resonator element according to the third embodiment of the invention, in which FIG. 11A is a top view, FIG. 11B is a cross-sectional view along BB ′, FIG. 11C shows an example of a cover mounting structure.

  As shown in FIGS. 11A and 11B, the actuator device 1B according to the present embodiment is the same as the above-described first embodiment except that the vibrating element 30B is configured by providing the beam portion 31B in a cantilever manner. It is. In the present embodiment, the same components as those described in the second embodiment are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIGS. 11A and 11B, the beam portion 31B is provided only on one side with respect to the frame 70, that is, in a cantilever shape. Further, the mass body 32B is provided at the distal end portion that is the free end side of the beam portion 31B. By adopting such a structure, the center of gravity of the mass body 32B is located on the extension line of the beam portion 31B, and stable vibration is possible even with a configuration supported on one side.

  In this configuration, in particular, in order to prevent bending due to its own weight, it is desirable that the Young's modulus in the length direction of the beam is large, and it is preferable to form the beam in the direction in which the <110> texture is formed.

Further, as shown in FIG. 11C, the cover member 40 is provided as in the first embodiment described above while adopting the structure of the actuator device 1B, and the vibration element 30B is disposed in the decompression space 50. Thus, the air resistance can be reduced and more stable vibration characteristics can be obtained.
(Embodiment 4)

  12A and 12B are schematic views illustrating an example of an actuator device including the resonator element according to the fourth embodiment of the invention, in which FIG. 12A is a top view, FIG. FIG.12 (c) is DD 'sectional drawing.

  As shown in FIG. 12, the actuator device 1C of the present embodiment includes a pair of first beam portions 31a that are bridged in a beam shape from a frame 70C, and a second beam portion 31b that bridges the pair of first beam portions 31a. And a plurality of piezoelectric elements 100 in the first beam portion 31a and a mass body 32C in the second beam portion 31b to configure the vibration element 30C. In the present embodiment, the same components described in the above-described first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  Specifically, the pair of first beam portions 31a that bridge the frame 70C substantially in parallel are provided with the piezoelectric elements 100 on both sides of the connecting portion with the second beam portion 31b. The piezoelectric element 100 is formed by laminating a piezoelectric film such as lead zirconate titanate, barium titanate, lead titanate or lead niobate, and an upper electrode (not shown). Although not shown, a voltage is applied to each piezoelectric element 100 from the drive circuit via the frame 70C and the upper electrode, and the piezoelectric element 100 is caused to bend and vibrate in opposite directions, thereby causing the first beam portion 31a. Torsion torque can be applied to the. Thereby, torsional vibration is excited in the vibration element 30C. The optical mirror unit 322C is arranged on both surfaces of the mirror arrangement unit 311C. By adopting such a structure, when the reflective film is formed, the film stress is balanced to prevent the deformation of the optical mirror portion 322C, and when the member having the mirror surface is joined, the center of gravity is obtained. It plays the role of balancing.

  The mass body 32C, the first beam portion 31a, and the second beam portion 31b, which are formed integrally with the frame 70C, are formed of work-hardening and age-hardening type Co—Ni based alloys, as in the first embodiment. . As in the present embodiment, when a piezoelectric film such as lead zirconate titanate (PZT) such as lead zirconate titanate (PZT) that causes a reaction between the metal material and lead due to heat treatment is used as the piezoelectric film of the piezoelectric element 100, Forming an intermediate layer for preventing lead diffusion between the films is preferable in terms of improving the piezoelectric characteristics. For forming the piezoelectric element 100, an aerosol deposition method (AD method) is preferably used.

  The first beam portion 31a on which the piezoelectric element 100 is formed is heat-treated together with the piezoelectric element 100, and the characteristics of the piezoelectric element 100 are improved and the age hardening of the Co—Ni based alloy is simultaneously performed. Thereby, the manufacturing process can be simplified. The heat treatment conditions are desirably performed at 500 to 700 ° C. for 1 to 3 hours in a reducing atmosphere. Here, since the age-hardened Co—Ni base alloy has excellent heat resistance, it is possible to heat-treat the piezoelectric film by forming the piezoelectric element 100 on the age-hardened Co—Ni base alloy. .

  The characteristics of the vibration element 30C are the same as those of the first embodiment described above, and the vibration element 30C can be similarly reduced in size. Further, in the present embodiment, since the driving voltage of the piezoelectric element 100 can be significantly reduced compared to the case where the piezoelectric element 100 is disposed by bonding or the like, the driving unit such as a power supply circuit can be downsized. .

In addition, in this embodiment, the structural modification of the actuator device 1C is shown, in that a work hardening and age hardening type Co—Ni based alloy is used for the first beam portion 31a and the second beam portion 31b. The same effects as those of the first embodiment described above can be obtained.
(Embodiment 5)

  FIG. 13 is a schematic diagram of an image forming apparatus including a resonator element according to the fifth embodiment of the invention.

As shown in FIG. 13, the image forming apparatus 200 of the present embodiment can apply the vibration element 30 or the like described in the first to fourth embodiments (illustrated as the vibration element 30 in FIG. 13). The light emitted from the laser beam 201 is reflected by the mirror of the vibration element 30 through the emission optical system 202, passes through the imaging optical system 203, and is scanned by the photoconductor 204. The scanned laser light is detected by the BD sensor 205, and a scanning angle control signal is output from the control circuit 206 based on the detection signal and fed back to the drive circuit 207 of the vibration element 30. The image forming apparatus 200 according to the present embodiment has the vibration element 30 including the vibration part (beam part) made of work-hardening and age-hardening type Co—Ni based alloy, which is advantageous for downsizing and jitter. Instability such as the above can be reduced and stable laser beam scanning is possible, and the scanning angle can be controlled with high accuracy.
(Embodiment 6)

  FIG. 14 is a schematic diagram of a video projection apparatus including a vibration element according to Embodiment 6 of the present invention.

  As shown in FIG. 14, the image projection apparatus 300 of the present embodiment can apply the vibration element 30 and the like (shown as the vibration element 30 in FIG. 14) described in the first to fourth embodiments. In addition, light emitted from the light source device 301 including the three primary colors of RGB is two-dimensionally scanned by the vertical scanning device 302 via the vibration element 30 and projected onto the screen 303 as an image.

  Further, the scanning speed of the vertical scanning device 302 is slower than that of the vibration element 30. The vertical scanning device 302 uses a galvanometer mirror that can be positioned with high accuracy by non-resonant driving. The scanning angle of the vibration element 30 is controlled by the drive circuit 305 based on a control signal output from the control circuit 304. Similarly, the scanning angle of the vertical scanning device 302 is controlled based on the output from the control circuit 304. The control circuit 304 changes the scanning angle of the vibration element 30 and the vertical scanning device 302 based on the setting of the projection field angle and the projection size by the input unit 306 and the distance measuring unit 307 and the size and aspect ratio of the image. The projection size of the image can be controlled by ON / OFF control of the light source device 301 without changing the scanning angle. However, by changing the scanning angle, the light source OFF time can be reduced and light can be used effectively. Can do.

  The image projection apparatus 300 of the present embodiment includes the vibration element 30 including the beam portion that constitutes the vibration portion made of work-hardening and age-hardening type Co—Ni-based alloy, which is advantageous for downsizing. Instability such as jitter can be reduced, and stable operation is possible even if the scanning angle is changed. In addition, since the distortion amplitude dependency of the vibration attenuation rate is small, there is no sudden increase in power consumption when the scanning angle is increased. Furthermore, the driving power of the light source device 301 can be reduced by the effective use of light. As a result, the volume of the drive unit and the battery can be reduced together with the miniaturization, and a small and high-performance video projector 300 can be realized.

DESCRIPTION OF SYMBOLS 1 Actuator apparatus 10 Board | substrate 20 Holding member 30 Vibration element 31 Beam part 311 Mirror installation part 32 Mass body 322 Optical mirror part 323 Magnet 40 Cover member 50 Decompression space 60 Frame 70 Electric field application means 75 Drive circuit 100 Piezoelectric element 200 Image forming apparatus 300 Video projection device

Claims (15)

  A vibration unit having a vibration characteristic in which a peak shape of a resonance characteristic curve indicating a relationship between a change amount of a resonance frequency and a magnitude of a distortion amplitude is line symmetric, and a drive unit that vibrates the vibration unit. And a vibration element.   At least one of a vibration part having a vibration characteristic in which the peak shape of a resonance characteristic curve showing a relationship between the amount of change in resonance frequency and the magnitude of strain amplitude is line symmetric, a drive part that vibrates the vibration part, and the vibration part And a decompression space forming part that forms a decompression space in which the part is disposed.   A vibration part having a vibration characteristic in which the peak shape of a resonance characteristic curve showing a relationship between the amount of change in the resonance frequency and the magnitude of the distortion amplitude is line symmetric, an optical mirror part provided in the vibration part, and vibrating the vibration part A vibration element comprising: a drive unit for causing the vibration element.   A vibration part having a vibration characteristic in which the peak shape of a resonance characteristic curve showing a relationship between the amount of change in the resonance frequency and the magnitude of the distortion amplitude is line symmetric, an optical mirror part provided in the vibration part, and vibrating the vibration part An oscillating element comprising: a driving unit that causes the squeezing unit to form a depressurizing space in which at least a part of the oscillating unit is disposed.   The optical mirror portion is provided on the vibrating portion, and has an outer shape larger than the width of the vibrating portion, and a portion protruding outward from a portion facing the vibrating portion gradually decreases toward the tip. The vibrating element according to claim 3 or 4, The vibration element according to claim 1, wherein the vibration unit has a strain amplitude larger than 3 × 10 ⁻³ .   The vibration element according to any one of claims 1 to 6, wherein a Q value indicating ease of vibration is 1000 or more.   The vibration element according to claim 1, wherein the vibration part exhibits non-magnetism.   The vibrating element according to claim 1, wherein the vibrating portion is provided in a beam shape.   The vibration element according to claim 1, wherein the vibration unit is provided in a cantilever shape.   The said drive part has a magnet provided in the said vibration part, and a magnetic field generation part which produces the magnetic field which acts on the said magnet, The any one of Claims 1-10 characterized by the above-mentioned. Vibration element.   The vibration element according to claim 1, wherein the driving unit includes a piezoelectric element capable of applying a voltage from the outside.   A vibration part having a vibration characteristic in which the peak shape of a resonance characteristic curve showing a relationship between the amount of change in the resonance frequency and the magnitude of the distortion amplitude is line symmetric, an optical mirror part provided in the vibration part, and vibrating the vibration part And a light source that irradiates the mirror surface of the optical mirror unit with light, and performs optical scanning based on vibration of the optical mirror unit by the vibration unit.   A vibration part having a vibration characteristic in which the peak shape of a resonance characteristic curve showing a relationship between the amount of change in the resonance frequency and the magnitude of the distortion amplitude is line symmetric, an optical mirror part provided in the vibration part, and vibrating the vibration part And a light source for irradiating light onto the mirror surface of the optical mirror unit, and projecting an image by optical scanning based on vibration of the optical mirror unit by the vibration unit .   A vibration part having a vibration characteristic in which the peak shape of a resonance characteristic curve showing a relationship between the amount of change in the resonance frequency and the magnitude of the distortion amplitude is line symmetric, an optical mirror part provided in the vibration part, and vibrating the vibration part An image forming apparatus comprising: a driving unit configured to drive; and a light source that irradiates a mirror surface of the optical mirror unit, and forms an image by performing light scanning based on vibration of the optical mirror unit by the vibration unit. .

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