JP2009139873A - Oscillation body structure body, oscillation body apparatus having oscillation body structure body and method of manufacturing them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method or the like of manufacturing an oscillation body structure body by which defect production rate is reduced, an adjustment process for adjusting the oscillation body is dispensed with or the number of processes or their contents are reduced. <P>SOLUTION: The oscillation body structure body is manufactured by the method of manufacturing including a forming process and a selection process. In the forming process, an elastic supporting part 110, a first oscillation body candidate part 111a which is a first candidate of the oscillation body and a second oscillation body candidate part 111b which is a second candidate of the oscillation body which are respectively connected to the both ends of the elastic supporting body 110 are formed. In the selection process, either one of the first oscillation body candidate part 111a and the second oscillation body candidate part 111b is selected as the oscillation body 112. In the forming process, the first oscillation body candidate part and the second oscillation body candidate part may be designed and formed in a same shape or a substantially in a same shape. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an oscillating body structure including an oscillating body, an oscillating body device having an oscillating body structure, a manufacturing method thereof, an optical deflector using the oscillating body device, an optical device such as an image forming apparatus using the optical deflector. It relates to equipment.

Conventionally, an optical deflector is used in an optical apparatus such as an image forming apparatus such as a copying machine or a laser beam printer, a bar code reader, or an image display apparatus that projects an image by scanning a laser beam.

In general, as an optical deflector that performs optical scanning by mechanical movement, a polygon mirror made up of a rotating polygon mirror, a galvano mirror made up of an oscillating reflector, and the like are known. In particular, in the galvanomirror type, a resonant optical deflector produced by processing a silicon substrate by micromechanics technology has been developed. This type can be expected to be reduced in size, weight, and cost, and an optical apparatus such as an image forming apparatus using such a resonant optical deflector has been proposed.

FIG. 4 is a perspective view showing such an optical deflector (see Patent Document 1). In the deflection element 65 of FIG. 4, the inner movable plate 656 oscillates independently around the first axis AX1 and the second axis AX2 orthogonal to each other. The mirror driving unit deflects and scans the light beam in the main scanning direction X by swinging the inner movable plate 656 about the first axis AX1. On the other hand, the position of the scanning light beam in the sub-scanning direction Y on the surface to be scanned can be adjusted by swinging the inner movable plate 656 about the second axis AX2. Therefore, even when the scanning position of the light beam on the surface to be scanned is deviated in the sub-scanning direction, the light beam can always be scanned with high accuracy by correcting the deviation. Thus, there are provided an optical scanning device capable of easily and accurately adjusting the scanning position of the light beam in the sub-scanning direction and performing optical scanning without error, and an image forming apparatus equipped with the optical scanning device. .
JP 2005-70708 A

However, the following points are pointed out in terms of fabrication and handling of the optical deflector.
(A) When the surface of the scanning mirror has scratches or defects, the product is a defective product, which may reduce the yield.
(B) When the natural frequency deviates from the target frequency due to variations in the shape of the manufactured scanning mirror and torsion spring, the frequency is adjusted by trimming or the like that removes or adds material using laser light or the like. This process is required.

In view of the above problems, the method for manufacturing an oscillator structure according to the present invention includes an elastic support portion and a forming step. In the forming step, an elastic support part, a first oscillator candidate part that is a first candidate of an oscillator that is connected to both ends of the elastic support part, and a second candidate that is a second candidate of the oscillator The oscillator candidate portion is formed. In the selection step, one of the first oscillator candidate part and the second oscillator candidate part is selected as an oscillator. Typically, in the forming step, the first oscillator candidate part and the second oscillator candidate part are designed and formed to have the same shape or substantially the same shape.

In view of the above problems, the method of manufacturing the oscillator device according to the present invention includes an elastic support portion, a forming step, and a fixing step. In the forming step, an elastic support part, a first oscillator candidate part that is a first candidate of an oscillator that is connected to both ends of the elastic support part, and a second candidate that is a second candidate of the oscillator The oscillator candidate portion is formed. In the selection step, one of the first oscillator candidate part and the second oscillator candidate part is selected as an oscillator. In the fixing step, the other oscillating body candidate part selected as the oscillating body among the first oscillating body candidate part and the second oscillating body candidate part is attached to the fixing member. Here, typically, in the forming step, the first oscillator candidate part and the second oscillator candidate part are designed and formed to have the same shape or substantially the same shape.

In view of the above problems, the oscillator structure of the present invention includes an elastic support portion, a first oscillator candidate portion and an oscillator that are first candidates of the oscillator connected to both ends of the elastic support portion. And a second oscillator candidate part that is a second candidate for moving objects. The first oscillator candidate part and the second oscillator candidate part have the same shape or substantially the same shape.

Further, in view of the above problems, an oscillator device according to the present invention includes the oscillator structure described above, and an oscillator candidate part having a smaller number of scratches or defects or an oscillator candidate having a natural frequency close to the target frequency. The part is a rocking body. Of the first oscillating body candidate part and the second oscillating body candidate part, another oscillating body candidate part selected as the oscillating body is attached to a fixing member. To do.

In view of the above problems, an optical apparatus according to the present invention includes a light source and the above-described oscillator device that is provided with a light reflecting portion in the oscillator and serves as an optical deflector, and deflects light emitted from the light source. And the target object is irradiated with at least a part of the deflected light.

According to the present invention, since the first oscillating body candidate portion and the second oscillating body candidate portion respectively connected to both ends of the elastic support portion are formed as described above, a more preferable one is selected as the oscillating body. Can do. Therefore, it is possible to reduce the defective product rate, or to eliminate the adjustment process for adjusting the oscillator, or to reduce the number of processes or the contents thereof.

In the present invention, a first oscillating body candidate portion which is a first candidate of an oscillating body connected to both ends of an elastic support portion such as a torsion spring and a bending deformation spring, and a second candidate of an oscillating body. Two oscillator candidate portions are formed. Conventionally, in an oscillating body structure, an oscillating body and a fixing portion (portion attached to a fixing member) are formed by designing respective portions for that purpose. Therefore, even after it is found that the oscillator part does not satisfy the target design value or the predetermined condition, or it is difficult to achieve the target design value even after adjustment, it is suddenly replaced. It was impossible to make the fixed part into a rocking body.

On the other hand, in the present invention, both are previously designed and formed as the oscillator candidate part. At this time, based on a target design value (natural frequency or resonance frequency, moment of inertia, shape, dimensions, etc.), two oscillator candidate portions are designed and formed with the elastic support portion interposed therebetween. Typically, it is designed and formed in the same shape or substantially the same shape. The almost same shape is, for example, a shape with a different natural frequency within a range of a few percent (at most 5 percent) or less, a difference in the presence or absence of a tab for adjusting the moment of inertia, and a difference in how to provide it. Refers to the shape. However, in some cases, the two oscillator candidate portions may be designed and formed in different shapes. For example, this is a case where the shape of the rocking body may be any one of the two.

The above design is performed in consideration of variations and defects that may occur in the manufacturing process. As a result, even if problems such as variations and surface defects occur in the actual manufacturing process, it is possible to increase the rate at which either can be used as it is or after being slightly adjusted. In this way, it is possible to reduce the defective product rate, or to eliminate the adjustment process for adjusting the oscillator, or to reduce the number of processes or the contents thereof. The above is the basic idea of the present invention.

Here, considering that the variation tends to occur in the same direction in the two oscillator candidate portions with respect to the intended design, it is typically preferable to design in the following three modes. is there. A description will be given assuming that the oscillator device is an optical deflector.

(1) Make both mirrors with the same size, use the less problematic side as the mirror side, and the more problematic side as the side to be attached to the fixed member. As a result, a defective product can be remedied and the yield can be improved (see the first embodiment described later). That is, in the formation process, both the first oscillator candidate part and the second oscillator candidate part are designed and formed so that each natural frequency becomes a target frequency. The smaller oscillator candidate part is selected as the oscillator.

(2) Design so that the natural frequency of both mirrors goes up and down across the target frequency, and use the one whose natural frequency achieved with variations near the target frequency as the mirror. This makes it possible to eliminate or reduce the step of adjusting the frequency by trimming or the like (see the second embodiment described later). That is, in the formation process, the first oscillator candidate part and the second oscillator candidate part are designed and formed so that the natural frequencies of the oscillator parts are up and down across the target frequency. The oscillator candidate portion whose number is closer to the target frequency is selected as the oscillator.

(3) One mirror is set to the target frequency and the other mirror frequency is designed to be larger or smaller. When the frequency of one mirror deviates from the target frequency due to variation, the other mirror is used. This can reduce the necessity of a frequency adjustment process such as trimming (see a third embodiment described later). That is, in the forming process, one of the first oscillator candidate part and the second oscillator candidate part is designed and formed so that its natural frequency becomes a target frequency, and the other is set so that its natural frequency is the target frequency. It is designed and formed to be larger or smaller. In the selection step, the oscillator candidate part whose natural frequency is closer to the target frequency is selected as the oscillator.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
A first embodiment such as a method of manufacturing an optical deflector 100 using the oscillator structure of the present invention will be described with reference to FIGS. 1 is a top view, and FIG. 2 is a cross-sectional view taken along line A1-A2 in FIG.

In this embodiment, in order to manufacture the oscillator structure, first, a resist is applied to the surface of a silicon substrate made of a single crystal with a thickness of about 10 μm, and photolithography is performed to manufacture a resist mask for dry etching. . At this time, the resist mask is designed so that the mass portions 111a and 111b can be formed in the same shape (that is, so as to have the same moment of inertia). The goal of this design is to give the two mass parts a predetermined resonance frequency, ie the natural frequency.

After the silicon substrate is attached to the adhesive substrate, RIE using inductively coupled plasma and BOSCH process is performed. In this way, the torsion spring 110 that is an elastic support part is formed, and the first oscillator candidate part 111a and the second oscillator candidate part 111b that are two mass parts connected to both ends of the torsion spring 110 have the same shape. To form. At this time, the bonded substrate functions as an etching stopper. Thereafter, the resist mask is removed, and the attached substrate is peeled off. Here, the BOSCH process is a method of selectively etching silicon in one direction with good anisotropy by alternately supplying an etching gas and side wall protection gas and switching between etching and side wall protection. By using this type of RIE, the torsion spring 110 and the side walls of the two mass portions 111a and 111b connected to both ends of the torsion spring 110 can be formed vertically. Here, in this way, the elastic support part, the first oscillator candidate part, and the second oscillator candidate part are integrally formed of silicon.

These elastic support portions and the two mass portions can also be formed by laser processing, press processing, or the like.

After forming a titanium film on the surface of the silicon substrate 121 including the mass parts 111a and 111b, a reflective film 123 is formed by forming a film of about 1000 mm of aluminum by vapor deposition, sputtering, or the like.

As described above, the two mass portions 111a and 111b connected to both ends of the torsion spring 110 are formed. Among these, the mass portion 111a with less problems, for example, the surface with less scratches or defects on the surface is used as the mass portion 112 on the side used as the oscillator for the optical scanning mirror. The more problematic side is used as the mass portion 114 on the side attached to the fixing member 113. The inspection of such a problem can be performed, for example, visually or with a microscope.

Next, a hard magnetic wire having a cross section of 0.5 mm × 0.5 mm square and a length of 1.8 mm is disposed on the back surface of the mass portion 114, fixed with an adhesive, and further magnetized to form a permanent magnet 115. Then, the electromagnetic coil 116 is arranged on the circuit board 117 so as to face the permanent magnet 115. The electromagnetic coil 116 and the fixing member 113 are connected to a circuit board 117 for driving the electromagnetic coil 116.

In this embodiment, the less problematic mass part is used as the mass part 112 on the side used as the oscillator for the optical scanning mirror, and the more problematic part is used as the mass part 114 on the side attached to the fixing member 113. To do. As a result, a defective product can be relieved and the yield can be improved.

Next, the structure of the optical deflector 100 using the oscillator structure according to the present embodiment will be described with reference to FIGS. The optical deflector 100 has a structure including a silicon substrate 121 processed by MEMS technology, a fixing member 113 for fixing the silicon substrate 121, a permanent magnet 115 bonded to the silicon substrate 121, and an electromagnetic coil 116. These components are installed on the circuit board 117. The overall size of the optical deflector 100 is, for example, about 5 mm in length, 10 mm in width, and about 3 mm in height.

In the present embodiment, the torsion spring 110 and the two mass portions 111 a and 111 b connected to both ends of the torsion spring 110 are integrally formed by the silicon substrate 121. The silicon substrate 121 is made of single crystal silicon and has excellent mechanical properties such as a large Young's modulus, a small specific gravity, and no plastic deformation. Therefore, it is possible to give a large natural frequency to the mass portion 112 on the side used as the oscillator.

A reflective film 123 is formed on the surface of the silicon substrate. The reflection film 123 serving as the light reflecting portion of the oscillating body is made of, for example, aluminum. On the back surface of the silicon substrate 121, a hard magnetic material having a cross section and a length as described above is disposed and fixed with an adhesive. This is magnetized to become a permanent magnet 115. The permanent magnet 115 is made of a material magnetized with a hard magnetic material such as samarium cobalt or neodymium iron boron.

The electromagnetic coil 116 has a wiring (not shown) wound in a circular shape along the XY plane (a plane parallel to the paper surface of FIG. 1). By supplying power from the power source to this, an N pole or an S pole appears on the upper surface of the electromagnetic coil 116 depending on the direction of the current. The wiring of the electromagnetic coil 116 is made of a low resistance metal such as copper or aluminum, and the number of turns is from several tens to several hundreds. Here, the size of the electromagnetic coil 116 is a diameter d = 3 mm and a height t = 2 mm. The circuit board 117 is made of a ferromagnetic material such as iron or permalloy, and has a role of connecting to the electromagnetic coil 116 and a role of shielding a magnetic field generated from the electromagnetic coil 116.

Next, a method of swinging the mass unit 112 on the side used as the swing body for the optical scanning mirror will be described. When a current I is passed through the electromagnetic coil 116, an N pole or an S pole appears on the upper surface of the electromagnetic coil 116. The generated magnetic field H is proportional to the product of the current I flowing through the electromagnetic coil 116 and the number N of turns of the electromagnetic coil 116. The magnetic field H acts on the magnetic poles of the permanent magnet 115, whereby the torsion spring 110 is deformed about the swinging central axis 118, and the mass portion 112 on the side used as the swinging body swings around the swinging central axis 118. When the current I is an alternating current, the mass unit 112 on the side used as the oscillator can be periodically displaced. Furthermore, by making the frequency of the alternating current substantially coincide with the natural frequency of the mass portion 112 on the side used as the oscillator, the resonance motion of the mass portion 112 with low power consumption becomes possible.

By appropriately changing the magnetic body, the electromagnetic coil, the elastic support portion, and the two mass portions, the swinging body swings around an axis extending in a direction perpendicular to the swinging central axis 118 in the plane of FIG. It is also possible to do. Here, the elastic support portion functions as a bending deformation spring.

According to this embodiment, the light source and the light deflector are provided, the light emitted from the light source is deflected by the light deflector, and at least a part of the deflected light is applied to a target object such as a photoconductor. An optical device for irradiation can be provided.

(Second embodiment)
A second embodiment such as a method of manufacturing the optical deflector 100 using the oscillator structure of the present invention will be described with reference to FIGS. FIG. 3 is a top view of the present optical deflector, and the basic configuration and driving method are the same as those in the first embodiment. Detailed description of the parts having the same functions is omitted.

The manufacturing method is similar to that of the first embodiment described above. The difference is that the two mass portions 111a and 111b connected to both ends of the torsion spring 110 are not formed in the same shape, but are designed and manufactured so that the moment of inertia (that is, the natural frequency) is different. is there. In FIG. 3, the mass part on the right side is slightly larger. This difference is about several percent or less in terms of resonance frequency, that is, natural frequency.

In the present embodiment, the torsion springs 110 are designed and manufactured so that the natural frequencies of the two mass parts 111a and 111b connected to both ends of the torsion spring 110 rise and fall across the target frequency. After fabrication, the one closer to the target frequency is used as the mass part 119 on the side used as the oscillator for the optical scanning mirror, and the other is used as the mass part 120 on the side attached to the fixing member 113.

The measurement of the natural frequency for such selection is performed as follows, for example. In an oscillating body structure formed by processing a wafer and comprising an elastic support part and two oscillating body candidate parts, a non-contact sound is generated at a position deviated from the axis of rotation of the oscillating body (see the oscillation center axis 118). Apply pressure. At this time, the frequency of the sound wave is scanned. Then, the torsional natural frequency of the oscillator is obtained from the added frequency or the detected frequency in a state where the oscillator responds torsion to the frequency. Based on the measurement results, the mass unit 119 on the side used as the rocking body is selected from the two rocking body candidate parts. That is, here, in the selection process, each natural frequency is detected by an excitation method in which the first oscillator candidate part and the second oscillator candidate part are pressurized through a space to examine the natural frequency. Then select one as the rocking body.

In the present embodiment, as described above, the natural frequency of the two mass portions 111a and 111b connected to both ends of the torsion spring 110 is designed to rise and fall across the target frequency. As a result, it is possible to eliminate the laser trimming and other frequency trimming steps required due to manufacturing variations, or to eliminate or reduce the number and contents of the steps.

The structure of the optical deflector 200 using this oscillator structure is similar to that of the first embodiment described above, as in the manufacturing method. The difference is that the two mass portions 111a and 111b connected to the both ends of the torsion spring 110 are not designed to have the same shape, but have shapes having different moments of inertia as described above. The reason why the above-described effects can be obtained by such design and production is that the variation tends to occur in the same direction in the two oscillator candidate portions from the intended design. In consideration of this, if the design is made as described above and any variation occurs, one of the oscillating body candidate parts approaches the target design, and this is used as the oscillating body. The mass part 119 may be used. Moreover, even if an adjustment process is required, since it is approaching the target design, the number or degree thereof can be reduced or reduced.

(Third embodiment)
A third embodiment such as a method of manufacturing an optical deflector 100 using the oscillator structure according to the present invention will be described with reference to FIGS. FIG. 3 is a top view of the present optical deflector, and the basic configuration and driving method are the same as those in the first and second embodiments described above. Detailed description of the parts having the same functions is omitted.

The manufacturing method is similar to that of the second embodiment described above. The difference is that with respect to the natural frequency of the two mass parts 111a and 111b connected to both ends of the torsion spring 110, one mass part is designed and made to match the target frequency, and the other mass part is made larger than the target frequency. Alternatively, it is to design and produce a smaller size.

In the present embodiment, the natural frequency of the two mass portions 111a and 111b connected to both ends of the torsion spring 110 is designed as described above to produce a structure. As a result, when the frequency deviates from the target frequency due to manufacturing variations, the need for a frequency adjustment process such as trimming can be reduced by using the other mass part as an oscillator for the optical scanning mirror. It becomes possible. The reason that this is possible is that the variation occurs in the same direction at the two mass parts, so when one of them varies in a direction away from the target frequency, the other becomes more likely to vary in the direction approaching the target frequency. .

The structure of the optical deflector 200 using this oscillator structure is similar to that of the second embodiment described above, as in the manufacturing method. The difference is that the two mass parts 111a and 111b connected to both ends of the torsion spring 110 are not the same shape, and one mass part is shaped to match the target frequency, and the other mass part has a higher or lower frequency. In this way, the shape of inertia is different.

The oscillator device can be used for an apparatus using an oscillator structure such as a sensor such as a potential sensor in addition to the optical device.

FIG. 3 is a top view illustrating a first embodiment of an optical deflector using the oscillator structure according to the present invention. It is sectional drawing explaining embodiment of the optical deflector etc. using the rocking | fluctuation body structure of this invention. FIG. 6 is a top view for explaining second and third embodiments of an optical deflector using the oscillator structure according to the present invention. It is a figure explaining the background art of this invention.

Explanation of symbols

100: Optical deflector
110: Elastic support (torsion spring)
111a: First oscillator candidate part (one of two mass parts connected to both ends of torsion spring 110)
111b: second oscillator candidate part (the other of the two mass parts connected to both ends of the torsion spring 110)
112, 119: Mass part on the side used as a rocking body
113: Fixed member
114, 120: Mass part on the side attached to the fixing member 113
115: Permanent magnet
116: Electromagnetic coil
118: Oscillation center axis

Claims (10)

An elastic support portion, and a first oscillator candidate portion that is a first candidate for an oscillator and a second oscillator candidate portion that is a second candidate for the oscillator connected to both ends of the elastic support portion, respectively. Forming step of forming,
A selection step of selecting any one of the first oscillator candidate part and the second oscillator candidate part as an oscillator;
A method for manufacturing an oscillating body structure characterized by comprising: An elastic support portion, and a first oscillator candidate portion that is a first candidate for an oscillator and a second oscillator candidate portion that is a second candidate for the oscillator connected to both ends of the elastic support portion, respectively. Forming step of forming,
A selection step of selecting any one of the first oscillator candidate part and the second oscillator candidate part as an oscillator;
A fixing step of attaching another oscillating body candidate part selected as the oscillating body to the fixing member among the first oscillating body candidate part and the second oscillating body candidate part,
A method of manufacturing an oscillator device characterized by comprising: The first or second rocking body candidate portion and the second rocking body candidate portion are designed and formed to have the same shape or substantially the same shape in the forming step. 2. The production method according to 2. 2. The method according to claim 1, further comprising a step of forming a light reflecting portion on at least one of the first oscillator candidate part and the second oscillator candidate part before or after the selecting step. 4. The manufacturing method according to any one of items 3. In the forming step, the first oscillator candidate part and the second oscillator candidate part are both designed and formed such that each natural frequency becomes a target frequency,
5. The manufacturing method according to claim 1, wherein, in the selection step, a oscillating body candidate portion with fewer scratches or defects is selected as the oscillating body. In the forming step, one of the first oscillator candidate part and the second oscillator candidate part is designed and formed so that its natural frequency becomes a target frequency, and the first oscillator candidate part And the other of the second oscillator candidate part is designed and formed such that its natural frequency is larger or smaller than the target frequency,
5. The manufacturing method according to claim 1, wherein, in the selection step, an oscillator candidate part whose natural frequency is closer to the target frequency is selected as the oscillator. . In the forming step, the first oscillator candidate part and the second oscillator candidate part are designed and formed such that each natural frequency is up and down across a target frequency,
5. The manufacturing method according to claim 1, wherein, in the selection step, an oscillator candidate part whose natural frequency is closer to the target frequency is selected as the oscillator. . An elastic support portion, and a first oscillator candidate portion that is a first candidate for an oscillator and a second oscillator candidate portion that is a second candidate for the oscillator connected to both ends of the elastic support portion, respectively. An oscillating body structure having
The oscillator structure according to claim 1, wherein the first oscillator candidate part and the second oscillator candidate part have the same shape or substantially the same shape. The oscillator structure according to claim 8,
Of the first oscillator candidate part and the second oscillator candidate part, the oscillator candidate part having less scratches or defects or the oscillator candidate part having a natural frequency close to the target frequency as an oscillator, An oscillator device characterized in that another oscillator candidate portion selected as the oscillator is attached to a fixed member. The light source and the oscillator device according to claim 9, wherein the oscillator has an optical deflector provided with a light reflecting portion,
An optical apparatus characterized in that light emitted from the light source is deflected by the optical deflector, and at least a part of the deflected light is irradiated onto a target object.

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