JP2013003522A - Manufacturing method and performance adjustment method of optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method and a performance adjustment method of an optical scanner, which stabilize the performance of a scanner which inclines a mirror part to cause light to scan, in a high level without adjusting a resonance frequency of the mirror part.SOLUTION: An optical scanner 2 includes: a fixed frame 4; a driving part 5 which is coupled with the fixed frame and has an electro-mechanical conversion part and an elastic deformation part made into one body; a movable frame 6 which is coupled with the driving part 5 via a shaft part 8 and can be inclined mainly in a first direction; and a mirror part 3 which is coupled with the movable frame 6 via a torsion bar 7 and is inclined mainly in a second direction orthogonal to the first direction. In the manufacturing method and the performance adjustment method of the optical scanner, a resonance frequency of the driving part 5 is adjusted to a prescribed driving part resonance frequency corresponding to a mirror part resonance frequency of the assembled mirror part 3.

Description

  The present invention relates to an optical scanning device manufacturing method and a performance adjustment method, and more particularly, to an optical scanning device manufacturing method and a performance adjustment method including a MEMS mirror.

  Conventionally, a laser printer, a laser projector, or the like provided with an optical scanner (optical scanning device) that scans laser light or the like is known. Some laser printers include a polygon mirror that scans reflected light by rotating a polygonal column mirror with a motor, a galvano mirror that rotates a plane mirror by an electromagnetic actuator, and the like.

  Optical scanners using these polygon mirrors and galvanometer mirrors are relatively large in size, so in order to achieve further miniaturization, integrated circuit manufacturing technology is applied to integrate components such as mirrors and elastic beams. Development of molded MEMS (Micro Electro Mechanical Systems) is advancing.

  Further, even in an image projection apparatus such as a laser projector, in order to obtain a more compact optical scanner (optical scanning apparatus), it has been sought to form a scanning mirror (mirror part) by MEMS. In addition, an image projection apparatus including an optical scanner using a MEMS mirror as a mirror unit has already been filed (for example, see Patent Document 1).

  In order to make the mirror portion of a small-sized optical scanner (optical scanning device) using MEMS have a large tendency, it is preferable that the drive frequency of the piezoelectric actuator matches the mechanical resonance frequency of the mirror portion. However, the resonance frequency may vary from product to product due to dimensional errors and processing variations during manufacture.

  For this purpose, an optical scanning device (optical scanner) has been filed (for example, an optical scanner) that allows mass pieces to be attached to the mirror portion, the resonance frequency is variable, and the resonance frequency of each product can be individually adjusted with high accuracy (for example, , See Patent Document 2).

JP 2010-266508 A JP 2004-219889 A

  By transmitting the mechanical displacement of the electromechanical transducer such as a piezoelectric element through the elastic deformation portion, the mirror portion can be made to tend. Further, by supporting the mirror part via the elastically deforming part and the thin beam, the mirror part can be made to tend to be larger by utilizing the resonance of the mirror part. However, as disclosed in Patent Document 2, in a configuration in which mass pieces are added to the mirror portion (or the mass pieces are removed) in order to adjust the resonance frequency of the mirror portion, the mirror portion passes through a thin beam. Therefore, there is a risk of breakage during processing, which causes a problem.

  In addition, if the resonance frequency of the mirror portion is different, it becomes necessary to drive the piezoelectric actuator at a frequency corresponding to the new resonance frequency. Therefore, a change in the resonance frequency of the mirror portion is not desirable due to system constraints.

  For this reason, it is preferable that the drive frequency of the piezoelectric actuator and the mechanical resonance frequency of the mirror part match without adjusting the resonance frequency of the mirror part, and the scanner performance to scan the light with a tendency to the mirror part is high. It is desirable that the optical scanner be stable and stable.

  In addition, it is preferable that the method and the method for adjusting the performance of the optical scanning device have a high level of scanner performance for scanning the light by tending to the mirror without adjusting the resonance frequency of the mirror.

  The present invention has been made in view of the above circumstances, and it is an optical scanning device that has a high level of scanner performance that scans light by tending to the mirror without adjusting the resonance frequency of the mirror. An object is to provide a manufacturing method and a performance adjustment method.

  In order to achieve the above object, the present invention provides a fixed frame, a drive unit coupled to the fixed frame, in which an electromechanical conversion unit and an elastically deforming unit are integrated, and coupled via the drive unit and a shaft unit. An optical scanning device comprising: a movable frame that can be tilted mainly in a first direction; and a mirror unit that is connected to the movable frame via a torsion bar and that is mainly inclined in a second direction orthogonal to the first direction. The manufacturing method includes an adjustment step of adjusting a resonance frequency of the driving unit to a predetermined driving unit resonance frequency corresponding to a mirror unit resonance frequency of the assembled mirror unit.

  According to the above configuration, the scanner performance of the mirror unit can be stabilized by adjusting the resonance frequency of the drive unit to a predetermined drive unit resonance frequency corresponding to the resonance frequency of the mirror unit. In addition, since it is not necessary to make adjustment on the fragile device side, which is a mirror portion, the method of manufacturing an optical scanning device improves the yield rate.

  According to the present invention, in the method of manufacturing the optical scanning device having the above configuration, the shaft portion includes a highly deformable structure portion having low rigidity so as not to affect the resonance frequency of the mirror portion and the drive portion. It is characterized by being. According to this configuration, the resonance frequency of the mirror part and the resonance frequency of the drive part can be controlled independently.

  According to the present invention, in the method of manufacturing an optical scanning device having the above-described configuration, the adjustment step performs an adjustment to make the drive unit resonance frequency higher or lower than the mirror unit resonance frequency by a predetermined frequency. According to this configuration, by adjusting to a slightly higher or lower drive unit resonance frequency close to the mirror unit resonance frequency, it is possible to construct a robust system that is strong against changes in the environment, etc. Therefore, the mirror part can be greatly tended.

  According to the present invention, in the method of manufacturing the optical scanning device having the above-described configuration, the adjusting step is performed by removing a part of the mass of the electromechanical conversion unit or by applying a part of the mass. According to this configuration, even if variations occur in the resonance frequency of the produced mirror part, even if variations occur in the characteristics of the electromechanical conversion part, by removing part of the mass of the electromechanical conversion part or applying part of the mass, The resonance frequency of the drive unit can be adjusted to an appropriate range, and an optical scanning device with stable scanner performance can be manufactured.

  According to the present invention, in the method of manufacturing the optical scanning device having the above-described configuration, the adjustment step is performed by removing a part of the mass of the integrated elastic deformation part and the electromechanical conversion part or by applying a part of the mass. It is characterized by that. According to this configuration, it is possible to manufacture an optical scanning device with stable scanner performance by adjusting the drive unit resonance frequency to an appropriate range by removing a part of the mass of the manufactured drive unit or adding a part of the mass. .

  According to the present invention, in the method of manufacturing the optical scanning device having the above-described configuration, the adjustment step is performed by adjusting a position where the elastic deformation portion and the electromechanical conversion portion are integrated. According to this configuration, the drive unit can be adjusted by adjusting the mounting position of the electromechanical conversion unit with respect to the elastically deformable part, even if the resonance frequency of the manufactured mirror unit varies or the characteristic of the electromechanical conversion unit to be mounted varies. By adjusting the resonance frequency within an appropriate range, an optical scanning device with stable scanner performance can be manufactured.

  According to the present invention, in the method of manufacturing the optical scanning device having the above-described configuration, the adjustment step is performed by adjusting the size of the electromechanical conversion unit with respect to the elastic deformation unit. According to this configuration, even if the resonance frequency of the manufactured mirror part varies or the characteristics of the produced electromechanical conversion part vary, the adjustment for changing the size of the electromechanical conversion part to be attached to the elastic deformation part Thus, the optical scanning device with stable scanner performance can be manufactured by adjusting the drive unit resonance frequency to an appropriate range.

  In the method of manufacturing an optical scanning device having the above-described configuration, the adjusting step may include adjusting a particle size of additive particles to be blended in an adhesive when the electromechanical conversion unit is attached to the elastically deforming unit. It is characterized by doing. According to this configuration, even if the resonance frequency of the produced mirror part varies or the characteristics of the produced electromechanical conversion part also vary, the particle size of the additive particles blended in the adhesive is adjusted and elastic deformation occurs. By changing the thickness of the adhesive layer when attaching the electromechanical conversion part to the part, the resonance frequency of the drive part can be adjusted to an appropriate range, and an optical scanning device with stable scanner performance can be manufactured.

  The present invention also includes a fixed frame, a drive unit coupled to the fixed frame, in which the electromechanical conversion unit and the elastically deforming unit are integrated, and the drive unit and the shaft unit coupled to each other mainly in the first direction. A method of adjusting the performance of an optical scanning device, comprising: a movable frame that can be tilted to a movable portion; and a mirror unit that is connected to the movable frame via a torsion bar and that is mainly inclined in a second direction orthogonal to the first direction, The resonance frequency of the drive unit is adjusted to a predetermined drive unit resonance frequency corresponding to the mirror unit resonance frequency of the assembled mirror unit.

  According to the above configuration, by adjusting the resonance frequency of the drive unit to a predetermined drive unit resonance frequency corresponding to the resonance frequency of the mirror unit, desired scanner performance can be exhibited and stabilized. In addition, since it is not necessary to adjust on the fragile device side called the mirror portion, the yield rate at the time of manufacturing the micro scanner is improved.

  According to the present invention, in the method for adjusting the performance of the optical scanning device having the above-described configuration, the shaft portion includes a highly deformable structure portion having low rigidity so as not to affect the resonance frequency of the mirror portion and the driving portion. It is characterized by having. According to this configuration, the resonance frequency of the mirror part and the resonance frequency of the drive part can be controlled independently.

  According to the present invention, in the method for adjusting the performance of the optical scanning device having the above-described configuration, the adjustment step of adjusting to the predetermined drive unit resonance frequency may be performed such that the drive unit resonance frequency is higher or lower than the mirror unit resonance frequency by a predetermined frequency. It is characterized by making adjustments. According to this configuration, by adjusting to a slightly higher or lower drive unit resonance frequency close to the mirror unit resonance frequency, it is possible to construct a robust system that is strong against changes in the environment, etc. Therefore, the mirror part can be greatly tended.

  According to the present invention, in the method of adjusting the performance of the optical scanning device having the above-described configuration, the adjustment step of adjusting to the predetermined drive unit resonance frequency may include removing part of the mass of the electromechanical conversion unit or applying part of the mass. It is characterized by being performed by. According to this configuration, even if variations occur in the resonance frequency of the produced mirror part, even if variations occur in the characteristics of the electromechanical conversion part, by removing part of the mass of the electromechanical conversion part or applying part of the mass, The resonance frequency of the drive unit can be adjusted to an appropriate range, and the scanner performance can be easily stabilized.

  Further, in the performance adjustment method of the optical scanning device having the above configuration according to the present invention, the adjustment step of adjusting to the predetermined drive unit resonance frequency may include removing part of the mass of the integrated elastic deformation unit and the electromechanical conversion unit, Or it is characterized by performing by giving a part of the said mass. According to this configuration, it is possible to easily stabilize the scanner performance by adjusting the drive unit resonance frequency to an appropriate range by removing a part of the mass of the manufactured drive unit or adding a part of the mass.

  According to the present invention, in the performance adjustment method of the optical scanning device having the above-described configuration, the adjustment step of adjusting to the predetermined drive unit resonance frequency is performed by adjusting a position where the elastic deformation unit and the electromechanical conversion unit are integrated. It is characterized by that. According to this configuration, the attachment position is adjusted according to the deviation of the resonance frequency that can be determined in advance by, for example, receiving inspection of the piezoelectric element, so that an appropriate drive part resonance frequency corresponding to the resonance frequency of the mirror part is exhibited. Can be adjusted.

  According to the present invention, in the performance adjustment method of the optical scanning device having the above-described configuration, the adjustment step of adjusting to the predetermined drive unit resonance frequency is performed by adjusting the size of the electromechanical conversion unit with respect to the elastic deformation unit. It is said. According to this configuration, even if the characteristics of the piezoelectric element itself vary due to shape errors or material lot fluctuations, by changing the size of each product, it is possible to drive appropriately according to the resonance frequency of the mirror part. It can adjust so that a part resonance frequency may be exhibited.

  According to the present invention, in the performance adjustment method for the optical scanning device having the above-described configuration, the adjustment step for adjusting to the predetermined drive unit resonance frequency is blended with an adhesive when the electromechanical conversion unit is attached to the elastic deformation unit. It is characterized by adjusting the particle size of the additive particles. According to this configuration, the resonance frequency of the drive unit can be adjusted by changing the particle diameter of the additive particles according to the resonance frequency of the manufactured mirror part or according to the characteristics of the piezoelectric element to be attached.

  According to the present invention, the resonance frequency of the drive unit is adjusted to a predetermined drive unit resonance frequency corresponding to the mirror unit resonance frequency of the assembled mirror unit, so that the mirror unit can be adjusted without adjusting the resonance frequency of the mirror unit. Accordingly, it is possible to obtain an optical scanning device manufacturing method and a performance adjustment method in which the scanner performance for scanning light tends to be stable at a high level.

1 is a schematic plan view of an optical scanning device according to the present invention. It is principal part sectional drawing of an optical scanning device. It is a figure which shows the relationship between a mirror part resonance frequency and a drive part resonance frequency. It is a top view explaining the 1st adjustment process of a resonant frequency adjustment part. It is a top view explaining the 2nd adjustment process of a resonant frequency adjustment part. It is a top view explaining the change of the adjustment part of a resonant frequency adjustment part. It is a figure which shows transition of the resonant frequency which changes corresponding to the change of an adjustment site | part. It is a top view explaining the 3rd adjustment process of a resonant frequency adjustment part. It is a figure which shows transition of the resonant frequency which changes according to a 3rd adjustment process. It is sectional drawing explaining the 4th adjustment process of a resonant frequency adjustment part. It is a figure which shows transition of the resonant frequency which changes according to a 4th adjustment process. It is a schematic explanatory drawing which shows the operating state of the mobile terminal provided with the optical scanning device which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the drawings. Moreover, the same code | symbol is used about the same structural member, and detailed description is abbreviate | omitted suitably.

  The method of manufacturing an optical scanning device according to the present invention includes a fixed frame, a drive unit coupled to the fixed frame, in which the electromechanical conversion unit and the elastic deformation unit are integrated, and the drive unit and the shaft unit. An optical scanning device 2 comprising: a movable frame that is connected and tiltable mainly in the first direction; and a mirror unit that is connected to the movable frame via a torsion bar and that is mainly inclined in a second direction orthogonal to the first direction. It is a manufacturing method. The optical scanning device 2 is installed in a projector 100 mounted on a mobile terminal 40 such as a mobile phone or a PDA (Personal Digital Assistant) shown in FIG. 9, for example, and the light is projected on the projection surface 41 in the horizontal direction (H direction) and Scan in the vertical direction (V direction).

  For example, image information input to the projector 100 is projected onto the projection surface 41 by using laser light as the light source and scanning the laser light in the horizontal direction (H direction) and the vertical direction (V direction) on the projection surface 41. To do. The projection surface 41 may be a screen prepared separately, but may be other than a screen. For example, a wall surface or the like may be used as the projection surface 41.

  By using RGB three-color light sources as light sources, a color image can be projected on the screen. At that time, the projection range and resolution of the video are determined by the tendency amount of the mirror part, and the quality of the video is determined. Therefore, it is preferable that the tendency amount of the mirror portion is large for improving the quality of the video.

  In addition, the mirror supported by the beam and the drive unit to which the piezoelectric element is attached have a configuration having independent resonance frequencies. The resonance frequency of the mirror unit (mirror unit resonance frequency) and the resonance frequency of the drive unit (drive unit) By making the resonance frequency closer, the tendency amount of the mirror portion can be increased.

  Next, an example of the optical scanning device 2 will be described with reference to FIG. The optical scanning device 2 is for two-dimensionally scanning laser light emitted from a light source, and has at least a mirror unit 3 that reflects the laser light toward a projection surface 41 (see FIG. 9). . The tilt angle (reflection angle) of the mirror unit 3 can be changed. By changing the tilt angle of the mirror unit 3, two-dimensional scanning of laser light by the optical scanning device 2 is performed.

  The mirror unit 3 is incorporated in the MEMS, and the MEMS in which the mirror unit 3 is incorporated is used as the optical scanning device 2. In addition, the optical scanning device 2 is substantially flat and has a small thickness, and the outer shape thereof is substantially square (for example, the length of one side is about 1 cm) in plan view.

  As a specific structure, the optical scanning device 2 includes a structure obtained by performing an etching process or the like on the silicon substrate. In addition to the mirror unit 3, the fixed frame 4, the driving unit 5, and the movable frame are included. 6 etc. are integrated. In the following description, an axis that crosses the center of the mirror unit 3 in the horizontal direction in the figure is an X axis, and an axis that crosses the center of the mirror unit 3 in the vertical direction in the figure is a Y axis. In other words, the point where the X axis and the Y axis are orthogonal to each other is the center of the mirror unit 3.

  The mirror part 3 is rotatable via a first shaft part (torsion bar 7) parallel to the Y axis and a second shaft part (shaft 8) parallel to the X axis and intersecting the first shaft part at a substantially right angle. is there. The fixed frame 4 is a part corresponding to the outer edge of the optical scanning device 2 and surrounds other parts (the mirror unit 3, the drive unit 5, the movable frame 6 and the like). That is, the optical scanning device 2 rotates by the rotation of the fixed shaft 4, the first and second shaft portions having different axial directions, and the first shaft portion, and the rotation of the second shaft portion. Generated by the mirror unit 3 that is rotated by, the movable frame 6 that surrounds the mirror unit 3 and the first shaft unit, and that is rotated by the rotation of the second shaft unit, the electromechanical conversion element unit, and the electromechanical conversion element unit. And an elastic deformation part that transmits the displacement to the tendency of the mirror part 3.

  The drive unit 5, which is a part where the elastically deforming unit and the electromechanical conversion element unit are integrated, is separated from the fixed frame 4 in the X-axis direction and is connected to the fixed frame 4 in the Y-axis direction. That is, the elastically deforming portion connects the second shaft portion (shaft 8) and the fixed frame 4, and the electromechanical conversion element portion has an electromechanical conversion element layer sandwiched between the positive electrode and the negative electrode. Further, the drive unit 5 includes four piezoelectric actuator units, and the four piezoelectric actuator units are arranged so as to be symmetric with respect to the X axis and the Y axis, respectively, and separated from each other. ing. The piezoelectric actuator unit as the drive unit 5 sandwiches a piezoelectric element (a material obtained by polarization treatment of a sintered body made of PZT or the like as a raw material) with a pair of electrodes, and serves as a region (the drive unit 5 of the silicon substrate). It is formed by affixing on the elastic deformation part).

  In such a drive unit 5, when a voltage is applied to the pair of electrodes, the piezoelectric element sandwiched between the pair of electrodes expands or contracts. When the piezoelectric element expands or contracts, the elastically deforming portion, which is the region that becomes the driving portion 5 of the silicon substrate, bends accordingly. That is, the drive unit 5 is driven by being supplied with electric power.

  Further, as shown in the figure, the movable frame 6 is a substantially rhombus-shaped frame located inside the drive unit 5. Both ends of the movable frame 6 on the X axis are connected to the drive unit 5 via the shaft 8 (second shaft portion), and the other parts are separated from the drive unit 5. Thereby, the movable frame 6 can be rotated around the X axis.

  A pair of torsion bars 7 (first shaft portions) extending along the Y-axis direction are provided inside the movable frame 6. The pair of torsion bars 7 are arranged so as to overlap the Y axis and be symmetric with respect to the X axis. Further, one end of each of the pair of torsion bars 7 is connected to an end of the movable frame 6 on the Y axis.

  And the mirror part 3 is arrange | positioned between each other end of a pair of torsion bars 7, and is supported by the other end. For this reason, the mirror part 3 is rotated around the X axis together with the movable frame 6, and is rotated around the Y axis with the torsion bar 7 as the rotation axis. The mirror part 3 is formed in a substantially circular shape, and is obtained by sticking a reflective film made of gold, aluminum or the like on the region to be the mirror part 3 of the silicon substrate.

  The optical scanning device 2 has the above structure. The scanning operation of the optical scanning device 2 is performed by adjusting the timing for driving (deforming) the four drive units 5 and vibrating the mirror unit 3 around the X axis and the Y axis. For example, the frequency when vibrating around the X axis is set to about 60 Hz, and the frequency when vibrating around the Y axis is set to about 30 kHz.

  More specifically, each of the four drive units 5 is denoted by reference numerals 5-1 to 5-4. When the mirror unit 3 is vibrated around the X axis, the drive units 5-1 and 5-3 are provided. , And the drive units 5-2 and 5-4 as the other set, the polarity of the voltage applied to each of the one set and the other set is reversed. Specifically, the drive units 5-1 and 5-3 that are one set are deformed in a direction that bends upward, and the drive units 5-2 and 5-4 that are the other set are bent in a direction that bends downward. When deformed, the mirror unit 3 rotates around the X axis together with the movable unit 6. Next, the drive units 5-1 and 5-3 that are one set are deformed in a direction that bends downward, and the drive units 5-2 and 5-4 that are the other set are deformed in a direction that bends upward. Then, the mirror unit 3 rotates together with the movable unit 6 in the reverse direction around the X axis. Thereby, the mirror part 3 vibrates around the X axis together with the movable frame 6, and the inclination of the mirror part 3 varies around the X axis. Since the torsion bar 7 is twisted in a direction perpendicular to the vibration direction around the X axis, it does not affect the vibration of the mirror portion 3 around the X axis.

  Further, when the mirror unit 3 is vibrated around the Y axis, the drive units 5-1 and 5-2 are set as one set, and the drive units 5-3 and 5-4 are set as the other set. The polarity of the voltage applied to each of the set and the other set is reversed. Specifically, the drive units 5-1 and 5-2 that are one set are deformed in a direction that bends upward, and the drive units 5-3 and 5-4 that are the other set are bent in a direction that bends downward. When deformed, the mirror unit 3 rotates around the Y axis together with the movable unit 6. Next, the drive units 5-1 and 5-2 that are one set are deformed in a direction that bends downward, and the drive units 5-3 and 5-4 that are the other set are deformed in a direction that bends upward. Then, the mirror unit 3 rotates together with the movable unit 6 in the reverse direction around the Y axis. Thereby, the mirror part 3 vibrates around the Y axis together with the movable frame 6, and the inclination of the mirror part 3 fluctuates around the Y axis.

  At this time, if the mirror unit 3 is tilted about the Y axis only by deforming the drive unit 5, the variation in the tilt of the mirror unit 3 about the Y axis becomes small. For this reason, when the scanning operation is actually performed, the frequency of the applied voltage to the drive unit 5 is set so that the mirror unit 3 resonates with the frequency of the voltage applied to the drive unit 5.

  By operating the optical scanning device 2 as described above, the mirror unit 3 can be rotated around two axes orthogonal to each other, and laser light can be two-dimensionally scanned by the single mirror unit 3. It becomes.

  By the way, in this embodiment, in order to easily adjust an unstable factor caused by a manufacturing error and stably obtain a large amount of deformation, the resonance frequency of the mirror unit 3 is not changed and the piezoelectric element side (driving unit side) is changed. The resonance frequency is adjusted. That is, in the optical scanning device 2 according to this embodiment, the resonance frequency of the drive unit 5 is set in advance to a frequency higher or lower than a predetermined reference frequency by a predetermined range, and further, the mirror unit resonance of the assembled mirror unit 3 is set. The drive unit is adjusted to a predetermined resonance frequency corresponding to the frequency.

  With the above configuration, the resonance frequency of the drive unit 5 is adjusted to be close to the mirror unit resonance frequency, and is adjusted to be higher or lower by a predetermined frequency than the mirror unit resonance frequency, thereby stabilizing the scanner performance of the mirror unit 3. It can be made. In addition, since it is not necessary to make adjustment on the fragile device side of the mirror unit 3, the yield rate is improved.

  In addition, even if the resonance frequency of the drive unit 5 is adjusted, the shaft unit 8 is a beam that connects the drive unit 5 and the movable frame 6 including the mirror unit 3 so that the resonance frequency of the mirror unit 3 is not affected. Is preferably provided with a highly rigid structure portion with low rigidity. Specifically, it is preferable that the shaft portion 8 includes a highly deformable structure portion having low rigidity so as not to affect the mutual resonance frequency of the mirror portion 3 and the drive portion 5. With such a configuration, the resonance frequency of the mirror unit 3 and the resonance frequency of the drive unit 5 can be controlled independently, and the mirror unit 3 tends to be greatly increased via the low-rigidity shaft unit 8. it can.

  This low-rigidity and high-deformation structure part can be realized, for example, by providing a meandering part made of a thin beam in a part of the shaft part 8.

  The resonance frequency of the drive unit 5 is preferably set to a slightly higher resonance frequency that is close to the resonance frequency of the assembled mirror unit 3. For example, the drive unit resonance frequency is set to a value about 5% higher than the mirror unit resonance frequency. By doing so, it is possible to construct a robust system that is strong against changes in the environment and the like.

  As shown in FIG. 2, the electromechanical conversion element layer includes a fixing portion 11 (corresponding to the fixing frame 4 to which the optical scanning device 2 is attached) and an elastic deformation portion 12 (corresponding to a part of the silicon substrate. A portion where the mechanical conversion element layer is integrated is equivalent to the drive unit 5), and electrode portions (a positive electrode portion 13 </ b> A and a negative electrode portion 13 </ b> B) are provided thereon, and a piezoelectric layer is provided via the adhesive layer 14. The element 51 is bonded and fixed. The piezoelectric element 51 is, for example, a unimorph electromechanical transducer that is sandwiched between a pair of electrodes of a positive electrode 15 and a negative electrode 16.

  The adhesive layer 14 is preferably an anisotropic conductive adhesive layer. If the adhesive layer 14 is an anisotropic conductive adhesive layer, the positive and negative electrode electrodes are formed by placing and pressing the piezoelectric element 51 sandwiched between the electrodes on the positive and negative electrode portions on the elastic deformation portion 12. The part (13A, 13B) and the electrode (15, 16) directly above can be electrically connected.

  That is, the electromechanical conversion element part (piezoelectric element 51) is joined to the electrode part provided on the elastic deformation part 12 via the anisotropic conductive adhesive layer. If it is this structure, the electrode part provided on the elastic deformation part 12 and the positive / negative electrode of the electromechanical conversion element part (piezoelectric element 51) arrange | positioned on it can be joined, without producing a short circuit. . That is, the electrode part for supplying electric power to the electromechanical conversion element part can be provided in the adhesive part with the elastic deformation part.

  This anisotropic conductive adhesive layer contains particles 14a that maintain the gap between the elastic deformation portion 12 and the electromechanical transducer element (piezoelectric element 51) at a predetermined interval that stabilizes the resonance frequency of the electromechanical transducer element. It is preferable to do. Moreover, it is preferable that this particle | grain 14a has electroconductivity. With this configuration, the gap between the elastic deformation portion 12 and the electromechanical conversion element portion (piezoelectric element 51) can be set to a predetermined interval via the conductive particles 14a blended in the anisotropic conductive adhesive layer. The resonance frequency of the drive unit 5 that affects the tendency amount of the mirror unit 3 can be stabilized, and as a result, the tendency amount of the mirror unit 3 can be stabilized.

  In this way, the resonance frequency of the drive unit 5 is stabilized, and the tendency amount of the mirror unit 3 can be increased by bringing the drive unit resonance frequency close to the resonance frequency of the mirror unit. That is, by setting the drive unit resonance frequency to a predetermined resonance frequency close to the mirror unit resonance frequency, the mirror unit 3 can be stably and greatly increased.

  As described above, the optical scanning device 2 is formed of a structure obtained by performing an etching process or the like on a silicon substrate, and in addition to the mirror unit 3, the fixed frame 4, the drive unit 5, and the movable frame 6. And so on. Thus, since the mirror part 3, the drive part 5, and the movable frame 6 are integrally formed, it is possible to reduce the size. Further, since the resonance frequency of the drive unit 5 is close to the resonance frequency of the mirror unit 3, a large amount of deformation can be obtained, and as a result, the mirror unit 3 can be sufficiently prone.

  For example, as shown in FIG. 3, when the mirror part resonance frequency MR is 29.2 kHz, the resonance frequency DR of the drive part is set to 30.6 kHz, which is about 5% higher than that. Although it is most efficient to make these two resonance frequencies coincide with each other, the resonance frequency of the drive unit 5 to which the piezoelectric element is attached is set to about 5 with respect to the resonance frequency of the mirror portion in consideration of the resonance frequency variation due to the environment. It is used as a robust system that is resistant to changes in the environment.

  When the difference width between the mirror part resonance frequency and the drive part resonance frequency changes due to a shape error or a lot fluctuation of a material such as a piezoelectric element at the time of manufacturing, performance varies from product to product. Therefore, it is preferable to adjust the drive unit resonance frequency to an appropriate value according to the mirror unit resonance frequency when a drive unit is manufactured by attaching a piezoelectric element to a predetermined part. That is, in the performance adjustment method of the optical scanning device according to the present invention, the resonance frequency of the drive unit is adjusted to a predetermined drive unit resonance frequency corresponding to the mirror unit resonance frequency of the assembled mirror unit to stabilize the scanner performance. Is. Note that a robust system that is resistant to changes in the environment and the like can also be constructed by lowering the resonance frequency DR of the drive unit by a predetermined frequency from the mirror unit resonance frequency MR.

  Next, a method for adjusting the performance of the optical scanning device for correcting the drive unit resonance frequency to a desired value will be described with reference to FIGS.

  To adjust the resonance frequency of the drive unit, there are a post-adjustment that is adjusted after the drive unit is once manufactured, and a pre-adjustment that is adjusted in advance according to the component characteristics. As a post-adjustment, a part of the mass of the electromechanical conversion unit once manufactured, a part of the mass, or a part of the mass of the drive unit in which the electromechanical conversion unit and the elastic deformation unit are integrated An adjustment process performed by removal or partial application of mass is employed. In addition, as pre-adjustment, an adjustment process performed by adjusting the piezoelectric element application position of the drive unit, an adjustment process of adjusting the size of the piezoelectric element applied to the drive unit, and adhesion when the piezoelectric element is applied to the drive unit And an adjustment step of adjusting the particle size of the additive particles to be blended in the agent.

  For example, part of the mass of the electromechanical conversion unit and the drive unit is removed by removing a predetermined portion of the drive unit by laser processing. Further, part of the mass is given by attaching a resin or the like to a predetermined part. The adjustment of the piezoelectric element attaching position of the driving unit is performed by adjusting the attaching position according to the deviation of the resonance frequency that can be determined in advance by an acceptance inspection of the piezoelectric element. For example, when the plate thickness of the received piezoelectric element is thick, the resonance frequency becomes high if it is applied as it is at a predetermined position. Therefore, in advance, the device is devised so as to lower the resonance frequency by bringing the position to be applied closer to the shaft portion. Further, the size of the piezoelectric element to be attached may be adjusted instead of changing the position to be attached. Further, the resonance frequency of the drive unit can be adjusted by adding particles having a predetermined particle diameter of an adhesive used for attaching the piezoelectric element and adjusting the distance from the elastically deforming part.

  For example, FIG. 4 shows a first adjustment process for removing a predetermined portion of the drive unit 5 such as an electromechanical conversion unit by laser processing. As shown in the figure, a portion near the fixed portion side away from the shaft portion 8 of the drive portion 5 is laser processed to remove a predetermined amount. Thus, since the micro scanner 1A provided with the removal portion R1 on the fixed portion side removes a part of the vibration node, the rigidity becomes weak and the resonance frequency of the drive portion 5 can be lowered.

  Further, the optical scanning device 2B shown in FIG. 5 shows an example in which a removal portion R2 is provided on the displacement side close to the shaft portion 8. In this second adjustment step, not the vibration node but the belly is shaved, and the mass of the drive unit 5 is reduced, so that the resonance frequency is increased. That is, when the resonance frequency of the drive unit 5 is to be increased, the displacement side of the drive unit 5 is removed by a predetermined amount, and when the resonance frequency of the drive unit 5 is to be decreased, the fixed part side of the drive unit 5 is removed by a predetermined amount. Good.

  The shape to be removed may be semicircular as shown or circular. Further, the size may be a single predetermined amount or a plurality may be removed so that the total amount becomes a predetermined amount, and can be appropriately adjusted according to the incorporated mirror portion or the attached piezoelectric element. In this way, a predetermined portion from the fixed portion side of the drive unit 5 to the displacement unit is used as a resonance frequency adjustment unit, and the resonance frequency of the drive unit 5 is brought close to the resonance frequency of the mirror unit 3 through this resonance frequency adjustment unit. Desired scanner performance can be exhibited and stabilized.

  Next, the transition of the resonance frequency that changes corresponding to the change of the adjustment region will be described with reference to FIGS. 6A and 6B. For example, when the removal unit R1 provided in the drive unit 5 (5-3) is changed from the fixed unit side to the displacement side in the direction indicated by the arrow DX in the drawing as in the optical scanning device 2C illustrated in FIG. 6A, The resonance frequency changes as shown in FIG. 6B.

  A frequency curve SC1 shown in FIG. 6B shows a change in the resonance frequency that changes in response to a change in the adjustment site indicated by the arrow DX. The horizontal axis of this figure represents the position of the adjustment part from the fixed part side to the tip side that is the displacement side, and the vertical axis represents the frequency increase / decrease%. In addition, this frequency increase / decrease is aimed at a range of ± 3%.

  This is because ± 1 kHz is used as the adjustment width when the drive unit is driven at 30 kHz. Since the optical scanning device 2C of the present embodiment uses the natural vibration of the secondary mode, the resonance frequency is changed to a quadratic curve as shown in the frequency curve SC1 shown in the figure. It is good to adjust using the region AR1 and the region AR2. That is, the resonance frequency can be adjusted in a range of ± 3% by using the −region AR1 and the + region AR2 as a resonance frequency adjusting unit.

  Next, with reference to FIGS. 7A and 7B, a description will be given of a third adjustment step performed by adjusting the piezoelectric element attaching position of the drive unit, and the transition of the resonance frequency corresponding to the change in the attaching position of the piezoelectric element. In the third adjusting step, the sticking position is adjusted in accordance with the deviation of the resonance frequency that can be determined in advance by, for example, an acceptance inspection of the piezoelectric element. For example, as in the optical scanning device 2D shown in FIG. 7A, the attachment position of the piezoelectric element 51 to be attached to the drive unit 5 (5-1) is moved from 51A to 51B, and the position away from the shaft part 8 is approached to the shaft part 8. When changed to the position, the resonance frequency changes as shown in FIG. 7B.

  A frequency curve SC2 illustrated in FIG. 7B indicates a resonance frequency corresponding to a change in the position of the adjustment portion indicated by the arrow DX. The horizontal axis of this figure represents the position of the adjustment part from the fixed part side away from the shaft part on the displacement side to the position approaching the shaft part, and the vertical axis represents the frequency increase / decrease%. The increase / decrease of the frequency is aimed at ± 3% as described above.

  Thus, if the sticking position of the piezoelectric element 51 is 51A (position away from the shaft portion 8), the resonance frequency can be increased by + 3%, and the sticking position of the piezoelectric element 51 is close to 51B (shaft portion 8). Position), the resonance frequency can be lowered by -3%. That is, the resonance frequency can be adjusted in a range of ± 3% by using the pasting positions 51A to 51B as the resonance frequency adjusting unit.

  Further, instead of the third adjustment step performed by adjusting the piezoelectric element attaching position of the drive unit, a pre-adjustment for adjusting the size of the piezoelectric element attached to the drive unit may be performed. With this adjustment process, even if the characteristics of the piezoelectric element itself vary due to shape errors or material lot fluctuations, the size of each product can be changed to suit the resonance frequency of the mirror. It is possible to adjust so as to exhibit a proper drive unit resonance frequency.

  Next, with reference to FIGS. 8A and 8B, a fourth adjustment step for adjusting the particle size of the additive particles to be blended in the adhesive when the piezoelectric element is applied to the drive unit, and when this piezoelectric element is applied The transition of the resonance frequency that changes corresponding to the adjustment of the distance from the elastic deformation portion by adding particles having a predetermined particle size of the adhesive used in the above will be described.

  For example, this adhesive is an adhesive that forms an anisotropic conductive adhesive layer, and is a ceramic ball (added particles) having a predetermined particle size (for example, 10 μm) obtained by applying an electrically conductive coating to an insulating epoxy resin. A mixture of particles 14a) is used. The amount of the ceramic balls is, for example, about 5% by weight. An epoxy resin containing 5% of the ceramic balls is applied to the electrode portion formed on the elastically deformed portion, and the piezoelectric element is placed thereon. Then press, heat cure and fix. Then, the particle size of the additive particles (particles 14a) defines the interval between the piezoelectric element to be bonded and the elastically deformed portion.

  Therefore, for example, when a particle 14a having a particle diameter of 10 μm is added, the distance E between the piezoelectric element and the elastically deforming portion becomes 10 μm, and exhibits a resonance frequency corresponding to this structure. When the particle 14a having a particle diameter of 20 μm is added, the distance between the piezoelectric element and the elastically deforming portion becomes 20 μm, and a new resonance frequency corresponding to this structure is exhibited.

  That is, the resonance frequency of the drive unit can be adjusted by changing the particle size of the additive particles. For example, as shown in FIG. 8A, a silicon substrate having a thickness of 50 μm is used as the elastically deformable portion 12, and a 70 μm thickness is provided via an adhesive layer 14 on which an epoxy adhesive to which particles 14a having a predetermined particle diameter are added is applied. A drive unit to which a piezoelectric element was attached was produced, and the resonance frequency was measured.

  As a result, as shown in the frequency curve SC3 of FIG. 8B, in this embodiment, when the particle size is 10 μm, it is −1%, and from this point, the resonance frequency increases as the particle size increases. I know that. That is, the resonance frequency can be adjusted between -1% and + 3% by changing the particle diameter of the adhesive used when attaching the piezoelectric element.

  As described above, the method of adjusting the performance of the optical scanning device according to the present invention includes a fixed frame, a drive unit coupled to the fixed frame, in which the electromechanical conversion unit and the elastic deformation unit are integrated, and the drive unit. And a movable frame that is connected via a shaft part and is tiltable mainly in a first direction, and a mirror part that is connected to the movable frame via a torsion bar and that is mainly inclined in a second direction orthogonal to the first direction; In this optical scanning device, the resonance frequency of the drive unit is adjusted to a predetermined drive unit resonance frequency corresponding to the mirror unit resonance frequency of the assembled mirror unit to stabilize the scanner performance.

  In addition, the adjustment process for adjusting the resonance frequency includes an adjustment method performed by removing a part of the mass of the electromechanical conversion unit or the drive unit or by applying a part of the mass, and an adjustment performed by adjusting the piezoelectric element pasting position of the drive unit. At least one of a method, an adjustment method for adjusting the size of the piezoelectric element to be attached to the drive unit, and an adjustment method for adjusting the particle size of the additive particles to be mixed in the adhesive when the piezoelectric element is attached to the drive unit.

  Next, a method for manufacturing the optical scanning device according to the present invention will be described. The manufacturing method of the optical scanning device according to the present invention stabilizes the scanner performance by using the above-described optical scanning device performance adjustment method. That is, a fixed frame, a drive unit connected to the fixed frame, in which the electromechanical conversion unit and the elastic deformation unit are integrated, and the drive unit and the shaft unit are connected to each other and can be tilted mainly in the first direction. A method of manufacturing an optical scanning device comprising: a movable frame; and a mirror unit that is connected to the movable frame via a torsion bar and that is mainly inclined in a second direction orthogonal to the first direction. The scanner performance is stabilized by adjusting the frequency to a predetermined drive unit resonance frequency corresponding to the mirror unit resonance frequency of the assembled mirror unit.

  In addition, the adjustment process for adjusting the resonance frequency includes an adjustment method performed by removing a part of the mass of the electromechanical conversion unit or the drive unit or by applying a part of the mass, and an adjustment performed by adjusting the piezoelectric element pasting position of the drive unit. At least one of a method, an adjustment method for adjusting the size of the piezoelectric element to be attached to the drive unit, and an adjustment method for adjusting the particle size of the additive particles to be mixed in the adhesive when the piezoelectric element is attached to the drive unit. Moreover, the adjustment process which combined these may be sufficient.

  By adopting such a manufacturing method, the scanner performance can be stabilized without changing the resonance frequency of the mirror portion. In addition, since it is necessary to perform adjustment work on the fragile device side, which is a mirror part, it is possible to obtain a method of manufacturing an optical scanning device that improves the yield rate without causing product destruction during the work.

  As described above, according to the manufacturing method and the performance adjustment method of the optical scanning device according to the present invention, the resonance frequency of the driving unit is set to a frequency that is higher or lower than a predetermined reference frequency in advance and assembled. Since the drive unit is adjusted to a predetermined drive unit resonance frequency according to the mirror unit resonance frequency of the mirror unit, the scanner performance for scanning the light with a tendency to the mirror unit is stabilized at a high level without adjusting the resonance frequency of the mirror unit. An optical scanning device can be manufactured.

  In addition, an adjustment method performed by removing a part of the mass of the electromechanical conversion unit or the drive unit or by applying a part of the mass, an adjustment method performed by adjusting the piezoelectric element pasting position of the drive unit, and a piezoelectric element pasted on the drive unit Since there is an adjustment step including at least one of an adjustment method for adjusting the size and an adjustment method for adjusting the particle size of the additive particles blended in the adhesive when the piezoelectric element is attached to the drive unit, the resonance frequency of the mirror unit The scanner performance can be stabilized by adjusting the resonance frequency of the driving unit without changing the frequency. In addition, since the scanner performance can be stabilized without changing the resonance frequency of the mirror portion, the yield rate is improved without causing product destruction during operation.

  Therefore, the manufacturing method and the performance adjustment method of the optical scanning device according to the present invention can be suitably used for image projection means having stable scanner performance and requiring mass production.

2, 2A-2D Optical scanning device 3 Mirror part 4 Fixed frame 5 Drive part 6 Movable frame 11 Fixed part 12 Elastic deformation part 14 Adhesive layer 14a Particle (addition particle)
15 Positive electrode 16 Negative electrode DR Drive part resonance frequency MR Mirror part resonance frequency R1, R2 Removal part (resonance frequency adjustment part)
41 Projection surface 51 Piezoelectric element (electromechanical transducer)
100 projector

Claims (16)

A fixed frame, a drive unit coupled to the fixed frame, in which the electromechanical conversion unit and the elastic deformation unit are integrated, and a movable unit that is coupled via the drive unit and the shaft unit and is tiltable mainly in the first direction. A method of manufacturing an optical scanning device comprising: a frame; and a mirror unit that is connected to the movable frame via a torsion bar and that is mainly inclined in a second direction orthogonal to the first direction,
A method of manufacturing an optical scanning device, comprising: an adjustment step of adjusting a resonance frequency of the driving unit to a predetermined driving unit resonance frequency corresponding to a mirror unit resonance frequency of the assembled mirror unit.   2. The optical scanning device according to claim 1, wherein the shaft portion includes a highly deformable structure portion having low rigidity so as not to affect a mutual resonance frequency of the mirror portion and the driving portion. Manufacturing method.   3. The method of manufacturing an optical scanning device according to claim 1, wherein in the adjustment step, the drive unit resonance frequency is adjusted to be higher or lower than the mirror unit resonance frequency by a predetermined frequency.   4. The method of manufacturing an optical scanning device according to claim 1, wherein the adjustment step is performed by removing a part of the mass of the electromechanical conversion unit or applying a part of the mass. 5.   The said adjustment process is performed by partial removal of the mass of the said elastic deformation part and the said electromechanical conversion part which were integrated, or the partial provision of the said mass, The one in any one of Claim 1 to 3 characterized by the above-mentioned. Manufacturing method of the optical scanning device.   4. The method of manufacturing an optical scanning device according to claim 1, wherein the adjustment step is performed by adjusting a position where the elastic deformation portion and the electromechanical conversion portion are integrated. 5.   The method of manufacturing an optical scanning device according to claim 1, wherein the adjusting step is performed by adjusting a size of the electromechanical conversion unit with respect to the elastically deforming unit.   The said adjustment process is performed by adjusting the particle size of the addition particle | grains mix | blended with the adhesive agent at the time of sticking the said electromechanical conversion part on the said elastic deformation part, Either of Claim 1 to 3 characterized by the above-mentioned. The manufacturing method of the optical scanning device of description. A fixed frame, a drive unit coupled to the fixed frame, in which the electromechanical conversion unit and the elastic deformation unit are integrated, and a movable unit that is coupled via the drive unit and the shaft unit and is tiltable mainly in the first direction. A performance adjustment method for an optical scanning device, comprising: a frame; and a mirror unit that is connected to the movable frame and a torsion bar and that is mainly inclined in a second direction orthogonal to the first direction,
A method for adjusting the performance of an optical scanning device, wherein the resonance frequency of the drive unit is adjusted to a predetermined drive unit resonance frequency corresponding to a mirror unit resonance frequency of the assembled mirror unit.   10. The optical scanning device according to claim 9, wherein the shaft portion includes a highly deformable structure portion having low rigidity so as not to affect a mutual resonance frequency of the mirror portion and the driving portion. Performance adjustment method.   11. The adjustment step of adjusting to the predetermined drive unit resonance frequency adjusts the drive unit resonance frequency to be higher or lower than the mirror unit resonance frequency by a predetermined frequency. Method for adjusting the performance of the optical scanning apparatus of the present invention.   The adjustment step of adjusting to the predetermined drive unit resonance frequency is performed by removing a part of the mass of the electromechanical conversion unit or applying a part of the mass. A method for adjusting the performance of the described optical scanning device.   The adjusting step for adjusting to the predetermined drive unit resonance frequency is performed by removing a part of the mass of the integrated elastic deformation unit and the electromechanical conversion unit or by applying a part of the mass. Item 12. A method for adjusting the performance of an optical scanning device according to any one of Items 9 to 11.   The adjusting step for adjusting to the predetermined drive unit resonance frequency is performed by adjusting a position where the elastically deforming unit and the electromechanical conversion unit are integrated. Method for adjusting performance of optical scanning device.   The optical scanning device according to claim 9, wherein the adjustment step of adjusting to the predetermined drive unit resonance frequency is performed by adjusting a size of the electromechanical conversion unit with respect to the elastic deformation unit. Performance adjustment method.   The adjustment step of adjusting to the predetermined drive unit resonance frequency is performed by adjusting the particle size of the additive particles blended in the adhesive when the electromechanical conversion unit is attached to the elastic deformation unit. The method for adjusting the performance of the optical scanning device according to claim 9.

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