JP2003098469A - Optical scanning device and image forming apparatus - Google Patents

Abstract

[PROBLEMS] To improve bonding between substrates, wire bonding to a drive circuit, and sealing in a multiple reflection type optical scanning device. SOLUTION: A micro mirror 10 and a counter mirror substrate 2 are provided.
A light reflecting device that joins 0 and enlarges a scanning angle by multiple reflection between a movable mirror and a counter mirror. Opposing mirror substrate 2
The bonding surface 0 is in contact with and bonded to the micromirror substrate only at a portion of the substrate of the micromirror 10 that avoids the electrode wiring. The electrode wiring is exposed from the penetrating portion provided on the opposing mirror substrate 20, and after the electrode metal 14 is additionally formed on the exposed portion, wire bonding (15) and sealing (16) are performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device for performing optical scanning by swinging a minute movable mirror, and more specifically, to a movable mirror between a movable mirror and a mirror facing the movable mirror. The present invention relates to an optical scanning device of a type in which an incident light beam is multiply reflected and then emitted.

[0002]

2. Description of the Related Art Conventionally, in a writing optical system of a laser printer, an angle of view (hereinafter referred to as a scanning angle) is generally obtained by scanning a light beam in a main scanning direction using a polygon mirror. An image is formed on the photoconductor. In order to improve the image quality of the printer, it is necessary to reduce the focused spot diameter of the beam, but since the focused spot diameter is proportional to the product of the laser wavelength and the focal length, shorten the laser wavelength. A method and a method of shortening the focal length can be considered. When shortening the wavelength of the laser, it is necessary to use a blue laser diode and design an optical system such as a lens corresponding to the blue laser diode. In addition, when the focal length is shortened, it is necessary to bring the optical system after the deflecting unit that deflects the light beam closer to the photoconductor. However, it is necessary to adopt a divided scanning method in which a plurality of modularized deflection units are arranged in the main scanning direction.

When optical scanning is performed using a polygon mirror or a galvanometer mirror, the rotation speed of the polygon mirror or galvanometer mirror must be further increased in order to achieve higher resolution images and higher speed printing. There is a limit to the speedup in terms of durability, heat generation due to windage, and noise.

As a new optical scanning device capable of solving such a problem, silicon micromachining is used,
An optical scanning device has been proposed in which a movable mirror and a torsion bar that axially supports the movable mirror are integrally formed of a Si substrate (Japanese Patent Nos. 2722314 and 3011144). Since this optical scanning device reciprocally oscillates the movable mirror by utilizing resonance, it has advantages of low power consumption for driving and low noise even though high speed operation is possible.

Such an optical scanning device (micromirror)
There are three types of driving methods for the movable mirror, which are an electromagnetic force method, a piezoelectric method, and an electrostatic force method. Electromagnetic force system,
The piezoelectric method easily obtains a large scanning angle, but since it uses a permanent magnet or a piezoelectric element, it has many parts and is difficult to miniaturize. On the other hand, the electrostatic force method is easy to miniaturize, but on the other hand,
Since the scanning angle and the driving voltage have a trade-off relationship, it is not easy to obtain a large scanning angle. In order to cover this weak point of the electrostatic force method, there is an attempt to obtain a large scanning angle by providing a mirror (opposing mirror) at a position facing the movable mirror and causing multiple reflection between the movable mirror and the opposing mirror. .

[0006]

Generally, the micromirror and its driving circuit are connected by wire bonding. At that time, the electrode wiring (including the lead wiring and the bonding pad) of the micromirror is usually formed on the substrate member on which the movable mirror is axially supported, and wire-bonded from there to the lead terminal on the drive circuit side. However, in the optical scanning device that performs multiple reflection between the facing mirror and the movable mirror, since the structure is such that the substrate on the moving mirror side and the substrate on the facing mirror side face each other and are bonded, the bonding between the facing substrates is good. Therefore, it is necessary to devise a method for wire bonding between the substrate on the movable mirror side and the drive circuit.

Accordingly, it is an object of the present invention to provide a multiple reflection type optical scanning device which is improved in connection between substrate members and wire bonding with a driving circuit.

Further, in the multi-reflection type optical scanning device, since the movable mirror and the opposed mirror are closely opposed to each other, when the movable mirror is operated in the atmosphere, the scanning angle obtained by the air damping effect is reduced. It is smaller than the theoretical expansion ratio. Therefore, in the multiple reflection type optical scanning device, it is important to hermetically or vacuum seal the swing space of the movable mirror.

Therefore, another object of the present invention is to
An object of the present invention is to provide an improved multiple reflection type optical scanning device with respect to the sealing structure of the swing space of the movable mirror.

Another object of the present invention is low power consumption,
An object of the present invention is to provide an image forming apparatus such as a printer which can perform high-speed recording with low noise.

Other objects of the present invention will be apparent from the following description.

[0012]

According to a first aspect of the present invention, there is provided an optical scanning device having a swingable movable mirror, and electrode wiring for driving the movable mirror is formed. A second substrate member having a facing mirror for facing the movable mirror is joined to the first substrate member,
An optical scanning device configured to emit a light beam that has entered the movable mirror after being reflected between the movable mirror and the counter mirror, and is characterized in that the first scanning device of the second substrate member is provided. The joint surface with the substrate member is in contact with the first substrate member only at a portion on the first substrate member where the electrode wiring is avoided.

Another feature of the optical scanning device according to the present invention is, as described in claim 2, in the structure according to claim 1, in that the joint surface of the second substrate member with the first substrate member is joined. The step is provided at a portion facing the electrode wiring and a portion other than the portion.

Another feature of the optical scanning device according to the present invention is, as in claim 3, in the structure of claim 1 or 2, wherein the second substrate member is provided with a penetrating portion, and the electrode wiring is provided. Is partly exposed from the through portion.

Another feature of the optical scanning device according to the present invention is that, as in claim 4, in the structure of claim 3, the penetrating portion is sealed by a sealing member.

Another feature of the optical scanning device according to the present invention is, as described in claim 5, in the structure of claim 3, an electrode metal is additionally formed on a portion of the electrode wiring exposed in the penetrating portion. To be done.

According to a sixth aspect of the present invention, in the image forming apparatus for optically writing on the photoconductor to form an electrostatic latent image on the photoconductor, the image forming apparatus as the optical writing means is provided. An optical scanning device according to any one of claims 1 to 5 is used.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical scanning device according to the present invention will be described with reference to FIGS.

FIG. 1A is a schematic plan view showing a planar structure of an optical scanning device, and FIGS. 1B to 1E are schematic sectional views for explaining a sectional structure and a manufacturing process. . As shown in FIGS. 1B to 1E, this optical scanning device has a basic structure in which an opposed mirror substrate 20 is opposed to and bonded to a micromirror 10.

First, referring to FIG. 2, the micro mirror 10
The outline of the structure and the manufacturing method thereof will be described. Figure 2 (a)
Is a plan view of the micro mirror 10, and FIG. This cross-sectional view shows a section taken along the line abcdefgh in the plan view.

The micromirror 10 shown here is of an electrostatic drive type. The substrate 1, the movable mirror 2, and the torsion bar 3 that pivotally supports the movable mirror 2 are integrally formed by semiconductor fine processing of the Si substrate. After that, the insulating film 4 is formed on the surface by the thermal oxidation method, and then the substrate electrode opening 5 is formed in the substrate 1 by etching. Next, a mirror metal 6 is formed on the movable mirror 2, a metal 7 for two drive electrodes and a substrate electrode metal 8 facing the free end of the movable mirror 2 are formed on the substrate 1 simultaneously or sequentially. . Finally, the glass substrate 9 is bonded to the lower surface of the substrate 1 by anodic bonding or the like, and the lower surface is sealed while securing the swing space of the movable mirror 2 to complete the electrostatically driven micromirror. Although this example has a two-sheet structure, it is also possible to obtain a similar structure by using only one Si substrate. Further, in this example, the free end (movable electrode) of the movable mirror 2 and the drive electrode (7) facing the free end are formed in a comb-teeth shape in order to increase the electrode area and lower the drive voltage. There is.

Next, with reference to FIG. 3, the opposed mirror substrate 20.
The structure of is explained. FIG. 3A shows the opposed mirror substrate 10
FIG. (B) to (d) are abc- in the same plan view.
It is a cross-sectional view taken along the line defgh, but shows a partially modified cross-sectional structure.

As shown in FIG. 3A, the opposed mirror substrate 2
No. 0 has through-holes 11 for mounting formed at the four corners. Further, the facing mirror substrate 20 has a step for the swinging space of the movable mirror, as shown by a broken line 12, on the side facing the micromirror, and two penetrating portions 11 shown from the swinging space.
A step corresponding to the electrode wiring of the movable mirror, which is communicated with, is formed, and a counter mirror metal 13 (counter mirror) is further formed.

As a material of the opposed mirror substrate 20,
A light-transmitting material such as glass or plastic is used, and a light-reflecting material mainly composed of metals such as aluminum, gold, and chromium is used as the facing mirror metal 13. After this,
The light-transmissive material and the light-reflective material are not limited to the above types, and may be any materials that satisfy desired optical constants (refractive index, transmittance, reflectance, etc.). The step for the swing space of the movable mirror and the communication step may have the same height as shown in FIG. 3 (b), or may be made higher than the step for the swing space as shown in FIG. 3 (c). It is also possible to lower the communication step. When a glass substrate is used as the substrate material, it is easy to increase the diameter, and there is a merit that a batch process with a Si wafer becomes possible.

Further, as shown in FIG. 3D, it is also possible to realize the same structure by joining two substrates 20a and 20b made of the same material or different materials.

The above-described micromirror 10 and the opposed mirror substrate 20 are bonded together to complete the optical scanning device. The manufacturing process thereof will be described with reference to FIGS. 1B to 1E.

First, as shown in FIG. 1B, the micro mirror 10 and the counter mirror substrate 20 are aligned and bonded. Opposed mirror substrate 20 on substrate 1 of micromirror 10
Are bonded, but different materials such as the substrate material and the electrode wirings (5, 7) are exposed on the bonding surface, and there is a step. If this is ignored and the joining surfaces are joined, problems occur in joining strength and reliability. Therefore, in the present invention, the joint surface of the counter mirror substrate 20 is brought into contact with and joined to the joint surface of the substrate 1 only at a portion avoiding the electrode wiring, so that a uniform and highly reliable joint can be achieved. obtain. Further, when the two are bonded by the adhesive, the excess adhesive escapes to the communicating step portion of the opposed mirror substrate 20, so that uniform adhesive bonding is possible. Further, the alignment at the time of bonding is configured such that the penetrating portion 11 of the opposed mirror substrate 20 and the pad portion of the electrode wiring of the micromirror 10 can be aligned.

Next, as shown in FIG. 1 (c), a pad portion metal 14 is additionally formed from the penetrating portion 11 of the counter mirror substrate 20 on a part of the exposed electrode wiring on the micromirror side. . Since the metal on the micromirror 10 side is preferred to have high reflectance and low film stress, the film thickness thereof is usually about one digit smaller than the film thickness required for the pad portion of the electrode wiring. Therefore, it is difficult to simultaneously form both of them at the same time due to the difference in desired material and film thickness, and it is necessary to additionally or separately form a metal film on the pad portion. The advantage of performing the metal film formation for the pad portion at this stage is that the through-hole portion 1 of the opposing mirror substrate 20 is
Since 1 is used as a self-alignment mask, it is possible to form a film with accurate position accuracy without causing a large increase in the number of steps. However, when using a Si substrate as the substrate material, it is preferable to use a high-resistance substrate because the drive electrodes at two locations may become conductive.

Next, as shown in FIG. 1D, the electrode wiring is connected to the external drive circuit by wire bonding 15. By providing the penetrating portion 11, a part of the exposed electrode wiring can be seen from the outside, which facilitates wire bonding mounting to the lead terminal of the external drive circuit.

Next, a sealing process is performed. Since the penetrating portion 11 for the drive electrode and the swing space of the movable mirror 2 are connected by the communicating step portion, as shown in FIG. 1E, the penetrating portion 11 for the drive electrode is made of, for example, an epoxy resin. Sealant 16
The rocking space can be hermetically or vacuum-sealed by sealing with. Since the sealing portion can be seen from above through the penetrating portion 11, the sealing operation can be easily performed.

Although the same penetrating portion 11 is used here for both wire bonding and sealing,
The sealing penetrating portion may be separately provided at a position closer to the swing space than the wire bonding penetrating portion. Alternatively, wire bonding may be performed after the pad metal is used as a sealant. Further, the mounting method is not limited to the wire bonding mounting, and for example, the penetration portion may be sealed with a conductive material and the FPC bonding may be performed.

The purpose of sealing is to hermetically seal with an inert gas so that it is less susceptible to the operating environment (humidity, temperature, etc.) and the operation reliability is improved. Also,
By sealing in a vacuum (a state of being decompressed with respect to atmospheric pressure), in addition to improving the above-mentioned operational reliability, it is possible to prevent the amplitude of the movable mirror from being reduced by the air damping effect, and to improve the Q value of the resonance characteristic. Can be improved. Desirably, a method of sealing with a vacuum (a state in which the pressure is reduced with respect to the atmospheric pressure) after the replacement with an inert gas is preferable. In an optical scanning device of the type in which an opposed mirror is opposed to a movable mirror like the optical scanning device of the present invention, the amplitude is likely to be reduced due to the air damping effect, and sealing is performed compared to a device having a structure without an opposed mirror substrate. The effect is large.

Another example of the facing mirror substrate 20 will be described with reference to FIG. 4A is a plan view and FIG. 4B is a cross-sectional view taken along the line abcdefgh of the plan view. The facing mirror substrate 20 shown here has the same basic structure as the example shown in FIG. 3, but a non-light-transmitting material is used as the substrate material. Therefore, an entrance opening 17 and an exit opening 18 for the light beam are formed on both sides of the facing mirror metal 13. For example, a Si substrate can be used as the substrate material. The use of a Si substrate has the advantages that the bonding with the micromirror is the same material bonding, and the batch process on the Si wafer is possible.

When the optical scanning device as shown in FIG. 1 is constructed using the facing mirror substrate 20, a glass substrate, a prism mirror or the like is formed in the entrance opening 17 and the exit opening 18 for sealing. It is necessary to bond members made of a light-transmissive material.

The operation of the optical scanning device described above will be described. When a drive voltage is applied between the one drive electrode (7) and the movable mirror 2 (movable electrode), an electrostatic attractive force acts on the movable mirror 2 and the movable mirror 2 begins to tilt with the torsion bar 3 as a torsional rotation axis. The movable mirror 2 tilts to an angle that balances with the restoring force of the torsion bar 3 to return it to the horizontal state. In this state, release the application of drive voltage,
When a drive voltage is applied to the other drive electrode (7), the movable mirror 2 tilts to the opposite side. The movable mirror 2 can be reciprocally oscillated by alternately performing such driving. When the driving timing is brought close to the natural frequency of the movable mirror 2, a resonance state occurs, and the movable mirror 2 is driven with a low driving voltage.
A large deflection angle can be obtained.

When the movable mirror 2 is tilted, the mirror surface on the movable mirror 2, that is, the mirror metal 6 and the mirror surface of the counter mirror substrate 10, that is, the counter mirror metal 13 are not parallel to each other in the tilting direction, that is, the main scanning direction. Becomes The light beam incident on the mirror surface of the movable mirror 2 from the outside is repeatedly reflected between the non-parallel mirror surfaces and then emitted to the outside. Therefore, the scanning angle of the light beam is larger than the deflection angle of the mirror substrate 2. Can be expanded. FIG. 5 is a sectional view showing how the scanning angle is enlarged.

FIG. 5A is a sectional view in the main scanning direction,
The light beam 30 incident on the movable mirror 2 is repeatedly reflected multiple times between the non-parallel mirror surfaces. When the light is reflected once on the mirror surface of the movable mirror 2, the scanning angle becomes twice the deflection angle of the mirror substrate 2, and when it is incident on the movable mirror and reflected again, twice the deflection angle is added. It In this way, the scanning angle expands according to the number of times the light is reflected by the movable mirror. FIG. 5B is a sectional view in the sub-scanning direction. As seen in this figure, since the mirror surface on the movable mirror side and the opposing mirror surface are parallel to each other in the sub-scanning direction, the incident angle and the reflection angle are the same even when reflection is repeated a plurality of times.

When the optical scanning device is used in a printer or the like, since it is necessary to determine the natural frequency of the movable mirror, that is, the thickness and length of the torsion bar so as to match the recording speed, as the recording speed increases The rigidity of the torsion bar increases, and it is difficult to obtain the required deflection angle of the movable mirror. Even in such a case, by providing the facing mirror as in the optical scanning device of the present invention, it is possible to obtain a required scanning angle by deflecting the light beam a plurality of times by the movable mirror.

In the embodiment, the movable mirror is driven by generating electrostatic attraction. However, a coil is formed on the movable mirror so that the magnetic field lines pass in the direction intersecting the torsion bar. Even in the method of driving a movable mirror by applying a voltage to a coil to generate an electromagnetic force, a piezoelectric element is coupled to a torsion bar and a voltage is applied to the piezoelectric element to directly displace the movable mirror. The present invention can be similarly applied to an optical scanning device such as a generating system.

The optical scanning device of the present invention described above is suitable as an optical writing means in an image forming apparatus such as a racer printer or a digital copying machine. As an example of such an image forming apparatus, one embodiment of a laser printer according to the present invention will be described with reference to FIGS.

FIG. 6 is a schematic sectional view for explaining the overall structure of the laser printer. In the figure, reference numeral 500 denotes an optical writing unit incorporating the optical scanning device of the present invention, which forms an electrostatic latent image on the photosensitive drum 501 by scanning with a laser beam modulated by a recording signal. Around the photoconductor drum 501, a charging roller 502 for charging the photoconductor on the surface of the drum to a high voltage, and a developing roller for developing toner by attaching toner to the electrostatic latent image recorded by the optical writing unit 500. 503, a toner hopper 504 for storing toner, and a cleaning case 505 for scraping and storing the residual toner after being transferred onto a sheet with a blade are provided, and these are integrated units as a replaceable cartridge. The paper is supplied from the paper feed tray 506 by the paper feed roller 507 and conveyed counterclockwise. The sheet is sent by the registration roller pair 508 at the timing of printing, the image is transferred from the photosensitive drum 501 rotating in the same direction, fixed by the fixing roller 509, and then discharged to the sheet discharge tray 510. The device cover 511 is rotatably supported so that the optical writing unit 5 can be used when the cartridge is replaced or when the jammed paper is removed.
00 scanning lens (204) can be cleaned.

FIG. 7 is a perspective view of the optical writing unit 500. FIG. 8 is a perspective view showing the internal structure of the optical writing unit 500. Referring to FIG. 7 and FIG.
Reference numeral 0 is an optical scanning module incorporating the optical scanning device of the present invention. In this example, three optical scanning modules 200
However, they are mounted side by side in the main scanning direction on the printed circuit board 201 on which the electronic components forming the drive circuit of the LD and the drive circuit of the movable mirror are mounted. When mounting the support substrate 107
The bottom of (FIGS. 9 and 10) is a lead terminal 1 protruding downward.
15 (FIG. 9, FIG. 10) is passed through the through hole and abutted on the printed circuit board 201, the optical scanning modules are aligned on the substrate within the clearance of the through hole, and temporarily fixed, and other electronic components are attached. Soldered together and fixed together.

The printed circuit board 201 on which the optical scanning module 200 is mounted is abutted so as to close the lower opening of the housing 202, and is held and held between snap claws 202-1 provided in the housing 202. The printed board 201 is provided with a notch that engages with the width 207 of the snap claw, and is positioned in the main scanning direction, and at the same time, the engaging portion 206 is engaged with the board edge to fix the sub scanning direction. (See enlarged view A of FIG. 7). Further, the locking portion 206 is bent in the direction of the arrow a, so that the projection 205
Can be easily removed by pushing down the top edge of the board.

Inside the housing 202, a positioning surface for arranging and joining the first scanning lenses 203 constituting the image forming means in the main scanning direction, a positioning portion for holding the second scanning lens 204, and a synchronous mirror 208. Is formed.

In this embodiment, each optical scanning module 20
The second scanning lens 204 of No. 0 is integrally formed of resin, and the synchronous mirror 208 is also formed by being connected by a high-brightness aluminum plate, and is inserted and attached from the outside into the opening for emitting the light beam. In order to detect a beam on the scanning start side and the scanning end side of each optical scanning module 200, a synchronous detection sensor 209 (PIN photodiode) is arranged at an intermediate position and both end positions shared by adjacent optical scanning modules. , Mounted on the printed circuit board 201.

The synchronous mirror 208 is formed in a "dogleg" shape so that the reflection surfaces of the scanning start side and the scanning end side of the adjacent optical scanning modules face each other, each reflects a light beam, and a common synchronous detection sensor. Lead to 209. 210 in the figure
Is a connector, which is used for supplying power to all the optical scanning modules 200 and exchanging data signals. The photosensitive drum 50 is provided on both side surfaces of the housing 202.
Positioning member 2 having an abutting surface in conformity with a cylindrical surface provided concentrically with the drum in a cartridge holding 1
11 is attached. After the positioning member 211 is screwed to the protrusion 212, the L-shaped seat surface is attached to the pin 213 provided on the frame of the apparatus body by the spring 2.
Since it is mounted via 14, the cartridge is held in a state of being constantly pressed against the cartridge, and the positioning of the plurality of optical scanning modules with respect to the surface to be scanned can be collectively and reliably performed.

In this example, three optical scanning modules 2 are used.
However, the number of the optical scanning modules 200 may be increased or decreased according to the recording width of the laser printer.

Next, the structure of the optical scanning module 200 will be described with reference to FIGS. 9 and 10. FIG. 9 is a schematic sectional view for explaining the relationship between the internal structure of the optical scanning module 200 and peripheral members, and FIG. 10 is an exploded perspective view of the optical scanning module 200.

The optical scanning device 100 is constructed by assembling the micro mirror 10 shown in FIG. 2 and the counter mirror substrate 20 shown in FIG. 3 as described in FIG. Support substrate 1
07 is formed of a sintered metal or the like, and has lead terminals 115 inserted through an insulating material. The glass substrate 9 (FIG. 2) of the optical scanning device 100 of the optical scanning device 100 is bonded to the bonding surface 107-1 on the support substrate 107, and the coupling lens 110 is positioned and bonded to the V groove 107-2. -1
The LD chip 10 is mounted on the mounting surface 107-3 formed perpendicular to the
8 is mounted, and the monitor PD chip 109 for receiving the back light of the LD chip 108 is mounted on the mounting surface 107-4,
A prism mirror 112 is supported on the support portion 107-5 in order to return the light beam from the LD chip 108 toward the movable mirror 2 (FIG. 2) of the optical scanning device 100. In the coupling lens 110 having a shape obtained by cutting the upper and lower sides of a cylinder, the second surface is an axisymmetric aspherical surface, and the second surface is a cylinder surface having a curvature in the sub-scanning direction. The width and angle are set so that the optical axis of the coupling lens 110 is aligned with the light emitting point of the LD chip 108 when the cylindrical outer peripheral surface of the coupling lens 110 comes into contact with the V groove 107-2. The coupling lens 108 is adjusted in the optical axis direction so as to be a substantially parallel light beam in the main scanning direction and a convergent light beam that is converged by the movable mirror surface in the sub-scanning direction, and is bonded and fixed. The cut surface is formed in parallel with the generatrix of the cylinder surface so that positioning around the optical axis is performed. The leaf spring 116 includes an aperture 116-2 that shapes the light beam from the coupling lens 110 into a predetermined diameter, a spring portion 116-1 that biases the rear end of the prism mirror 112, and a movable mirror of the optical scanning device 100. An opening 116-3 is formed for passing the light beam deflected by the above.
The cover 111 is formed by sheet metal into a cap shape, and a glass plate 117 is joined to the light beam emission opening from the inside. The cover 111 is a support substrate 107.
It is fitted into the step portion 107-6 provided on the outer periphery of the. The optical scanning module 200 can be further hermetically sealed or vacuum sealed. The electrodes of the LD chip 108, the monitor PD chip 109, and the optical scanning device 100 are lead terminals 1
Connection is made by wire bonding with the end protruding upward from 15.

[0050]

According to the present invention, the following effects can be obtained. (1) Since different kinds of materials such as electrode wiring and substrate material are exposed on the bonding surface of the first substrate member (micromirror), and a step can be formed on portions other than the electrode wiring and the warp, these are ignored and the first When the bonding surface of the substrate member and the second substrate member (opposing mirror substrate) are brought into contact with each other and bonded, fluctuations in adhesive strength and reliability are likely to occur. According to the first aspect of the invention, only the portion of the joint surface of the second substrate member that avoids the electrode wiring on the first substrate member is brought into contact with the first substrate member. A highly flexible bond can be achieved. Moreover, even when a plurality of electrode wirings are formed on the first substrate member, there is no concern that they will be conducted through the second substrate member, so the material of the second substrate member is an insulating material. Without limitation, the selection range of the material of the second substrate member is expanded. (2) Further, according to the invention of claim 2, the first and second
When the substrate members of (1) are joined by an adhesive, the stepped portion serves as an escape route for the extra adhesive, so that uniform joining is possible. (3) Furthermore, according to the invention of the third aspect, it is possible to easily perform wire bonding mounting of the electrode wiring to the lead terminal of the external drive circuit through the penetrating portion. Further, by providing the penetrating portion at a plurality of positions with the movable mirror sandwiched therebetween, the penetrating portion can be used as a mark for alignment when the first substrate member and the second substrate member are joined. In addition, it is possible to properly use the penetrating portion such as the alignment mark penetrating portion, the sealing penetrating portion, the wire bonding mounting penetrating portion, and the like according to the function, which improves the process flexibility. (4) Further, according to the invention as set forth in claim 4, since the penetrating portion is a vent to the swinging space of the movable mirror, the swinging space is hermetically or vacuum-sealed to form the movable mirror. The resonance characteristics and reliability can be improved, and the sealing process for that can be facilitated. (5) The metal film used as the mirror surface on the movable mirror is preferably high in reflectance and low in film stress, and its film thickness is usually about an order of magnitude smaller than the film thickness required for electrode wiring pads. Therefore, it is difficult to form both of them at the same time because of the difference in desired material and film thickness, and it is necessary to additionally or separately form a metal film on the pad portion of the electrode wiring. Claim 5
According to the described invention, since the film formation can be performed by using the penetrating portion of the second substrate member as a self-alignment mask, the film formation with accurate position accuracy can be performed without causing a large increase in the number of steps. It will be possible. (6) Compared with a polygon mirror, the optical scanning device of the present invention consumes less power, generates less noise, and is capable of high-speed scanning. Therefore, according to the invention of claim 6, low power consumption and low power consumption are achieved. An image forming apparatus capable of high-speed recording due to noise can be realized.

[Brief description of drawings]

FIG. 1 is a plan view and a cross-sectional view for explaining an embodiment of an optical scanning device according to the present invention.

2A and 2B are a plan view and a cross-sectional view for explaining the structure of a micromirror.

3A and 3B are a plan view and a cross-sectional view for explaining the structure of a facing mirror substrate.

FIG. 4 is a plan view and a cross-sectional view for explaining another example of a facing mirror substrate.

FIG. 5 is a cross-sectional view in the main scanning direction and the sub scanning direction for explaining the light deflection operation of the light scanning device.

FIG. 6 is a sectional view for explaining an embodiment of a laser printer according to the present invention.

FIG. 7 is a perspective view for explaining the configuration of an optical writing unit.

FIG. 8 is a perspective view for explaining the configuration of an optical writing unit.

FIG. 9 is a cross-sectional view for explaining the configuration of the optical scanning module.

FIG. 10 is an exploded perspective view of the optical scanning module.

[Explanation of symbols]

1 substrate 2 movable mirror 3 torsion bar 5 Substrate electrode opening 7 mirror metal 7 Metal for drive electrodes (electrode wiring) 8 Substrate electrode metal (electrode wiring) 10 micro mirrors 11 Penetration part 12 steps 13 Opposite mirror metal 17 Entrance aperture 18 exit aperture 20 Opposing mirror substrate 200 Optical scanning module 500 optical writing unit 501 photoconductor drum 503 developing roller 504 toner hopper 509 fixing roller

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C362 BA17 BA49                 2H045 AB06 AB10 AB38 AB73                 5C051 AA02 CA07 DB24 DB30 DC07                       DD03                 5C072 AA03 BA01 DA04 DA21 HA02                       HA14 XA05

Claims (6)

[Claims] 1. A first substrate member having an oscillating movable mirror, and an electrode wiring for driving the movable mirror formed on a first substrate member, and an opposing mirror for facing the movable mirror. An optical scanning device having a configuration in which a second substrate member is joined and a light beam incident on the movable mirror is emitted after being reflected between the movable mirror and the counter mirror, An optical scanning device characterized in that a joint surface with the first substrate member is in contact with the first substrate member only at a portion on the first substrate member that is away from the electrode wiring. 2. The joint surface of the second substrate member with the first substrate member is provided with a step between a portion facing the electrode wiring and a portion other than the portion. Item 2. The optical scanning device according to item 1. 3. The optical scanning device according to claim 1, wherein the second substrate member is provided with a penetrating portion, and a part of the electrode wiring is exposed from the penetrating portion. 4. The optical scanning device according to claim 3, wherein the penetrating portion is sealed by a sealing member. 5. The optical scanning device according to claim 3, wherein an electrode metal is additionally formed on a portion of the electrode wiring exposed in the penetrating portion. 6. An optical scanning device according to claim 1, wherein the optical writing unit is an image forming apparatus that optically writes on a photosensitive member to form an electrostatic latent image on the photosensitive member. An image forming apparatus characterized in that the apparatus is used.