JP4226223B2 - Optical scanning apparatus and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical scanning device and an image forming apparatus, and more particularly to an optical scanning device used in a writing system such as a digital copying machine and a laser printer and used in a reading system such as a barcode reader.
[0002]
[Prior art]
Conventionally, an optical scanning device includes a light source unit in which the arrangement of a packaged semiconductor laser and a coupling lens is adjusted and assembled, a deflector such as a polygon mirror and a galvano mirror by precision machining, and a scanning lens composed of a plurality of sheets. Assembling is performed on the specified mounting part of the optical housing configured with high accuracy while managing the positional relationship with high accuracy, but because it relies on manual work, there is a limit to downsizing, and the assembly is expensive. There is a disadvantage that it takes.
[0003]
In contrast, in recent years, research on optical scanning devices using silicon micromachining technology has been advanced, and Japanese Patent No. 2,722,630, Japanese Patent No. 2,668,725 and Japanese Patent Laid-Open No. 4-96014. As disclosed in Japanese Laid-Open Patent Publication No. HEI, an optical scanning device in which a semiconductor laser chip and a bearing-integrated deflector are integrated on a single silicon substrate has been proposed. Since the semiconductor manufacturing process is used, there is an advantage that a very high positional accuracy can be secured and a plurality of devices can be manufactured simultaneously without human intervention.
[0004]
On the other hand, as an example using a semiconductor manufacturing process, the above-mentioned Japanese Patent No. 2,722,314 discloses a deflector in which a galvano mirror is integrally formed on a silicon substrate, and Japanese Patent Laid-Open No. 5-142405 discloses. A deflector having a diffraction grating formed on its surface is disclosed.
[0005]
[Problems to be solved by the invention]
However, there are limitations in the manufacturing process to create all the functions related to optical scanning on a single silicon substrate, and simply placing it one-dimensionally in the same layout as in the past is wasteful in terms of substrate size. Many. In addition, due to repeated thin film formation and trimming by etching, there is a drawback that the efficiency is very poor for a function that requires a certain thickness. On the other hand, semiconductor lasers and deflectors each require external power supply and exchange of control signals. However, there is a problem that the electrical wiring becomes difficult to handle due to downsizing of the optical scanning device. In addition, it is necessary to take measures against dust and dust that cause deterioration of optical performance and a short circuit, and the silicon substrate cannot be incorporated into the image forming apparatus.
[0006]
The present invention is intended to solve these problems. In addition to realizing a compact module as an optical scanning device, it is possible to improve the production efficiency by simplifying the manufacturing process, and to reduce the movable part of the deflector. An object of the present invention is to provide an optical scanning apparatus and an image forming apparatus that can reduce the load and reduce the power consumption by reducing the weight.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, an optical scanning device of the present invention having a light emitting source and a deflecting unit that deflects and repeatedly scans a light beam from the light emitting source is an electrode connected to the light emitting source and the deflecting unit. An electrode substrate, a deflection unit substrate provided with a movable part of the deflection unit, and a light source unit substrate mounted with at least a light emitting source and a monitor unit for detecting the light quantity of the light source. The light source part substrate is provided with an opening through which the light beam irradiated from the light source to the movable part of the deflecting unit passes, and the light beam is regulated by the opening diameter of the opening part. Is characterized in that the diameter of the light beam is defined . Therefore, an optical scanning device can be configured by simply stacking each substrate, while an unnecessary portion of a light beam diffused from a light emitting source such as a semiconductor laser reaches the deflecting means even when stored in a narrow space. Therefore, it is possible to reduce the number of parts, simplify the manufacturing process, and improve production efficiency.
[0008]
Further, by providing the positioning means for positioning a lens to couple the light beam from the outgoing light to the light source unit substrate, placement accuracy of the optical axis of the light emitting source and the lens can be secured easily, also the positioning means Since the adjustment in the direction of the optical axis with respect to the light emission point difference can be easily performed simply by moving the lens along the optical axis, the manufacturing process is simplified and the production efficiency can be improved.
[0009]
Further, by stacking frame substrates provided with deflecting reflecting means for guiding the light beam from the light source to the movable part of the deflecting means , the substrates are stacked in layers without the need for troublesome adjustment work. The arrangement accuracy of the light emitting source and the deflecting means can be easily ensured only by this, so that the manufacturing process is simplified and the production efficiency can be improved.
[0010]
Further, the monitor reflecting means for guiding the back light from the light source to the monitor means is provided on the frame substrate, and the monitor reflecting means is integrally formed on the frame substrate, so that the monitor means is inclined toward the light source side. This eliminates the need for troublesome structures and adjustment operations such as arranging the substrates, and by simply stacking the substrates in layers, the arrangement accuracy between the monitor means and the light emitting source can be easily secured, thereby simplifying the manufacturing process and improving production efficiency.
[0011]
Furthermore, as another invention, there is a feature in an image forming apparatus provided with the above-described optical scanning device.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An optical scanning device according to the present invention includes an electrode substrate having an electrode connected to a light emitting source and a deflecting unit, a deflecting unit substrate provided with a movable part of the deflecting unit, and a monitor that detects at least the light source and the light amount of the light emitting source. And a light source unit substrate on which the means is mounted and stacked in the order of an electrode substrate, a deflection unit substrate, and a light source unit substrate, and an opening through which a light beam irradiated from the light source to the movable unit of the deflection unit passes A light beam diameter of the light beam is defined by regulating the light beam with the opening diameter of the opening provided on the partial substrate .
[0013]
【Example】
FIG. 1A is an exploded perspective view showing the configuration of the optical scanning module in the optical scanning apparatus according to the first embodiment of the present invention, and FIG. 1B is a sectional view. In the figure, a lead terminal 102 is integrally formed on an electrode substrate 101 formed by ceramic molding, and a pair of magnets 103 are further provided. On the first silicon substrate 104, a mirror portion 106 supported by two torsion beams 105 is formed by anisotropic etching. A coil portion is formed on the periphery of the mirror portion 106 by vapor-depositing a metal film, and by passing an electric current through the coil, the torsion beam 105 is used as a rotation axis by electromagnetic force with the magnet 103 provided on the outer side. Amplitude. The central part of the mirror part 106 is formed as a reflecting surface by the metal coating. The mirror unit 106 can be made to swing with a lower load if the thickness of the torsion beam 105 is set so that the deflection speed matches the resonance frequency.
[0014]
A wiring pattern (not shown) is formed on the second silicon substrate 107 by vapor deposition of a metal film, and is connected to the lead terminals described above by wire bonding or the like. The semiconductor laser chip 108 can directly form an AlGaAs layer on the substrate of the first silicon substrate 104 by using an epitaxial technique to form a cladding layer and an active layer constituting the semiconductor laser. In this embodiment, the semiconductor laser chip 108 is manufactured separately. A semiconductor laser array chip having a plurality of light emitting sources is mounted via a submount so that the light emitting sources are arranged in parallel to the mounting surface. On the other hand, the monitoring photodiode 109 for detecting the back light of the semiconductor laser is formed by directly depositing a GaAs layer on the first silicon substrate 104. The coupling lens 110 is a cylindrical anamorphic lens having different curvatures in a direction parallel to the mounting surface and in a direction perpendicular to the mounting surface, and a part of the circumferential portion is applied to the V groove 111 formed on the second silicon substrate 107. Install in contact. The V groove 111 is formed so that the central axis of the coupling lens 110 coincides with the emission center of the semiconductor laser. In the semiconductor laser, two light emitting sources are formed at an interval of 14 μm, and on the surface to be scanned, each beam spot is arranged at a predetermined interval in a direction perpendicular to the mounting surface (sub-scanning direction) and simultaneously scans two lines. .
[0015]
Further, the frame substrate 112 is a single crystal Si substrate, and a reflecting portion 114 for guiding a light beam emitted from the coupling lens 110 by anisotropic etching to the mirror portion 106 through an aperture 113 formed on the second silicon substrate 107; A reflection portion 115 that guides the back light of the semiconductor laser to the photodiode 109 is formed. As shown in FIG. 1B, the light beam deflected and scanned by the mirror unit 106 is reflected between the back side of the second silicon substrate 107 and the reflecting unit 116 provided opposite to the back side of the second silicon substrate 107 with an interval of g = several hundred μm. In this embodiment, N = 4 reciprocations are reflected, and the light passes through the opening 117 and is emitted. In the case of the present embodiment, the amplitude angle θ of the mirror unit 106 is about 3 °, and the scanning angle is expanded to 3 ° × 2N = 24 ° while the reflection point is gradually moved in the sub-scanning direction by N = 4 reflections. Can be made. Here, the interval between the reflecting portion 115 and the mirror portion 106 is g, the incident angle of the light beam to the mirror portion 106 is β, the incident light beam diameter in the sub-scanning direction is ω (in the embodiment, the aperture 113 of the aperture 113). )), The interval g increases with each reflection in accordance with the amplitude angle θ of the mirror unit 106, so that at least the width L of the reflection unit is L> 2 (N−2) g · tan β + ω. Symmetrically with respect to the rotation axis, it gradually spreads toward the opening 117 from the center toward both ends. In this embodiment, the deflecting surface and the reflecting surface are opposed to each other substantially in parallel, but by setting the interval on the exit side g ₁ slightly wider (g ₁ ≧ g ₀ ) than the incident side g ₀ of the light beam. A margin for interference with the reflection part of the light beam on the emission side can be widened. It is not always necessary to reflect a plurality of times, and the opening 117 can be moved to the incident side to scan with one reflection.
[0016]
Further, the sealing plate 118 is made of a transparent member, and functions of a lens constituting a part of a scanning lens that forms an image of a light beam on a surface to be scanned, for example, a scanning line bending correction function due to oblique incidence on the mirror unit 106 Is provided to the exit window 119. In the figure, control circuits 120 and 121 are circuits for controlling current supply to the semiconductor laser 108 and the coil section, respectively, and are formed directly on the second silicon substrate 107 and the first silicon substrate 104, respectively. The above-described electrode substrate 101, the first silicon substrate 104, the second silicon substrate 107, the frame substrate 112, and the sealing plate 118 are sequentially stacked and bonded to form an optical scanning module.
[0017]
As shown in FIG. 2, the optical scanning module having the above configuration is arranged in plural on one electrical board 121 so that the main scanning is divided into a plurality of areas and the optical scanning module 122 is assigned to each area. Is done. A synchronization detection sensor 123 that detects a light beam on each scanning start side and a termination side, peripheral circuits of the control circuits 108 and 109, and the like are formed on the electrical board 121, and scanning lines between the optical scanning modules 122 are formed. The angle and the scanning position are matched and fixed by soldering. The light beam emitted from the optical scanning module 122 forms an image on the scanned surface 126 via the scanning lens 124. Each lens portion of the scanning lens 124 is integrally molded with resin, and the light beam emitted from the optical scanning module 122 is returned to the synchronization detection sensor 123 by the mirror 125 disposed in the vicinity of the scanning lens. The number of optical scanning modules 122 arranged in the example shown in FIG. 2 is three, but increases or decreases according to the total scanning width. In this embodiment, the main scanning is divided into a plurality of parts and scanned with two beams, but the configuration is the same regardless of whether the entire scanning width is scanned with one optical scanning module or scanning with one beam. It is.
[0018]
Hereinafter, another embodiment of the optical scanning module will be described. Since the means for mounting on the electrical board is the same, it is omitted.
[0019]
FIG. 3A is an exploded perspective view showing the configuration of the optical scanning module in the optical scanning device according to the second embodiment of the present invention, and FIG. 3B is a sectional view. In the figure, a lead terminal 202 is integrally formed on an electrode substrate 201 formed by ceramic molding. In the first silicon substrate 203, as shown in FIG. 3 (b), the deflection disk portion 204 is cut out from the polycrystalline Si layer deposited on the substrate by etching, separated from the stator portion 222, and then only the bearing clearance portion. The bearing portion is integrally formed through a process of forming an oxide film on the substrate and further depositing polycrystalline Si to form the shaft portion 223. A plurality of electrodes 206 serving as a stator are radially formed on the stator portion 222 by vapor-depositing a metal film, and electrodes 207 are also formed on the circumference of the deflection disk portion 204 so as to face the stator. Are driven by electrostatic force by sequentially switching the current application. Unevenness is formed in the deflection disk portion 204 in the circumferential direction by etching to form a diffraction grating 205, which is simultaneously coated with a metal film. The incident light beam is scanned at a reflection angle of about 1.5 times the angle of the grating which changes as the disk rotates. The surface of the diffraction grating 205 is divided into a plurality of regions in the circumferential direction, and in this embodiment, scanning for six surfaces is performed by one rotation.
[0020]
Similarly, a metal film is deposited on the second silicon substrate 208 to form a wiring pattern (not shown), which is connected to the lead terminal described above by wire bonding or the like. As in the first embodiment, the semiconductor laser chip 209 uses a semiconductor laser array chip having a plurality of light emitting sources manufactured separately, and is mounted via a submount 224 so that the light emitting sources are arranged perpendicular to the mounting surface. is doing. On the other hand, the monitoring photodiode 210 for detecting the back light of the semiconductor laser is formed directly on the second silicon substrate 208. The coupling lens 211 is a cylindrical anamorphic lens having different curvatures in a direction parallel to the mounting surface and a direction perpendicular to the mounting surface. The coupling lens 211 is installed in contact with a part of a circumferential portion in a V groove 212 formed on a silicon substrate. The V groove 212 is formed so that the central axis of the coupling lens 211 coincides with the emission center of the semiconductor laser. In the semiconductor laser, two light emitting sources are formed at an interval of 14 μm, and on the surface to be scanned, each beam spot is arranged at a predetermined interval in a direction perpendicular to the mounting surface (sub-scanning direction) and simultaneously scans two lines. . Similar to the first embodiment, the light beam emitted from the coupling lens 311 is laid out so as to be converged in the vicinity of the deflection surface in the sub-scanning direction. It is corrected by the surface.
[0021]
Further, the frame substrate 213 guides the light beam emitted from the coupling lens 211 to the deflecting disk unit 204 which is a deflector through the aperture 216 formed on the second silicon substrate 208 and the back light of the semiconductor laser. A reflection portion 215 that leads to the photodiode 210 is formed. In this example, as in the first example, a reflective portion was formed by anisotropic etching using a single crystal Si substrate. The aperture 216 shapes the beam diameter of the light beam and blocks ambient light. The light beam deflected and scanned by the deflecting disk unit 204 is emitted through the opening 217 provided in the second silicon substrate 208. The sealing plate 218 is made of a transparent member, and functions as a lens constituting a part of a scanning lens that forms an image of a light beam on a surface to be scanned, for example, a reflection angle correction function at a diffraction grating accompanying a wavelength change. To have. In the figure, control circuits 220 and 221 are circuits for controlling current supply to the semiconductor laser 209 and the stator electrode 206, respectively, and are formed directly on the second silicon substrate 208 and the first silicon substrate 203, respectively. . The above-described electrode substrate 201, first silicon substrate 203, second silicon substrate 208, frame substrate 213, and sealing plate 218 are sequentially stacked and joined to form an optical scanning module.
[0022]
Next, examples of the image forming apparatus using the optical scanning device of the above-described embodiment include a digital copying machine, a laser printer, and a plain paper facsimile. Of these, a digital copying machine will be described below as an example.
[0023]
FIG. 4 is a schematic sectional view showing the entire configuration of a digital copying machine as an image forming apparatus according to another invention. In the figure, the digital copying machine mainly includes a copying machine main body 300 and an image reading unit 400. The copying machine main body 300 controls the optical scanning device 301, cassettes 302 and 302 ′ for storing sheets, paper feed rollers 303 and 303 ′ for picking up sheets one by one from the cassettes 302 and 302 ′, and conveyance timing. A registration roller 304, a transfer charger 305, a photosensitive drum 306, a developing roller 307, a charging roller 308, and a process cartridge 309 integrated with each other, a fixing roller 310 containing a halogen heater, and a pressure roller 311, a conveyance roller 312, and a paper discharge roller 313. In addition, the image reading unit 400 forms an image on the photoelectric conversion element 403 such as a CCD through the imaging lens 402 through the image in the document reading unit 401 fixed on the document table, and moves the mirror group 404 in order. , Convert to electronic data. In the digital copying machine having such a configuration, first, a semiconductor laser is modulated in accordance with an image signal by the optical scanning device 301, and a latent image is formed on the photosensitive drum 306 uniformly charged by the charging roller 308. The toner image is developed by toner supplied from the developing roller 307. On the other hand, the paper taken out by the paper feed roller 303 or 303 ′ is conveyed by the registration roller 304 in accordance with the image writing timing of the optical scanning device 301, and the toner image is transferred. The transferred image is fixed by the fixing roller 310 and discharged.
[0024]
Further, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications and substitutions are possible as long as they are described within the scope of the claims.
[0025]
【The invention's effect】
As described above, the optical scanning device of the present invention having the light emitting source and the deflecting means for deflecting and repeatedly scanning the light beam from the light emitting source includes the electrodes connected to the light emitting source and the deflecting means. An electrode substrate, a deflecting unit substrate provided with a movable unit of the deflecting unit, and a light source unit substrate on which at least a light emitting source and a monitor unit for detecting the light quantity of the light emitting source are mounted. The light beam is formed by stacking in order, and an opening through which a light beam irradiated from the light source to the movable portion of the deflecting unit passes is provided in the light source unit substrate, and the light beam is regulated by the opening diameter of the opening. It is characterized in that the light beam diameter is defined . Therefore, an optical scanning device can be configured by simply stacking each substrate, while an unnecessary portion of a light beam diffused from a light emitting source such as a semiconductor laser reaches the deflecting means even when stored in a narrow space. Therefore, it is possible to reduce the number of parts, simplify the manufacturing process, and improve production efficiency.
[0026]
Further, by providing the positioning means for positioning a lens to couple the light beam from the outgoing light to the light source unit substrate, placement accuracy of the optical axis of the light emitting source and the lens can be secured easily, also the positioning means Since the adjustment in the direction of the optical axis with respect to the light emission point difference can be easily performed simply by moving the lens along the optical axis, the manufacturing process is simplified and the production efficiency can be improved.
[0027]
Further, by stacking frame substrates provided with deflecting reflecting means for guiding the light beam from the light source to the movable part of the deflecting means , the substrates are stacked in layers without the need for troublesome adjustment work. The arrangement accuracy of the light emitting source and the deflecting means can be easily ensured only by this, so that the manufacturing process is simplified and the production efficiency can be improved.
[0028]
Further, the monitor reflecting means for guiding the back light from the light source to the monitor means is provided on the frame substrate, and the monitor reflecting means is integrally formed on the frame substrate, so that the monitor means is inclined toward the light source side. This eliminates the need for troublesome structures and adjustment operations such as arranging the substrates, and by simply stacking the substrates in layers, the arrangement accuracy between the monitor means and the light emitting source can be easily secured, thereby simplifying the manufacturing process and improving production efficiency.
[0029]
Furthermore, as another invention, there is a feature in an image forming apparatus provided with the above-described optical scanning device.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a configuration of an optical scanning module in an optical scanning device according to a first embodiment of the present invention.
FIG. 2 is a perspective view showing an optical scanning device configured by arranging a plurality of optical scanning modules of the present invention.
FIG. 3 is a diagram illustrating a configuration of an optical scanning module in an optical scanning device according to a second embodiment of the present invention.
FIG. 4 is a schematic cross-sectional view showing an overall configuration of a digital copying machine as an image forming apparatus according to another invention.
[Explanation of symbols]
101; Electrode substrate, 102; Lead terminal, 103; Magnet,
104; First silicon substrate; 105; Torsion beam; 106; Mirror part;
107; second silicon substrate; 108; semiconductor laser chip;
109; photodiode, 110; coupling lens, 111; V-groove,
112; frame substrate; 113; aperture;
114, 115, 116; reflecting portion, 117; opening, 118; sealing plate,
119; exit window, 120, 121; control circuit.

Claims (6)

In an optical scanning device having a light emitting source and deflecting means for deflecting and repeatedly scanning a light beam from the light emitting source,
An electrode substrate comprising an electrode connected to the light source and the deflection means;
A deflection part substrate provided with a movable part of the deflection means;
A light source unit substrate on which at least the light emitting source and a monitor means for detecting the light quantity of the light emitting source are mounted;
And stacking in the order of the electrode substrate, the deflection unit substrate, the light source unit substrate,
An opening through which the light beam irradiated from the light emitting source to the movable part of the deflecting unit passes is provided in the light source unit substrate, and the light beam is regulated by the opening diameter of the opening to define the beam diameter of the light beam. An optical scanning device characterized in that:   2. The optical scanning device according to claim 1, wherein positioning means for arranging a lens for coupling a light beam from the light emitting source is provided on the light source unit substrate. 2. An optical scanning device according to claim 1, wherein a frame substrate provided with deflecting reflecting means for guiding the light beam from the light emitting source to the movable portion of the deflecting means is stacked.   2. The optical scanning device according to claim 1, wherein a reflection means for monitoring is provided on the frame substrate for guiding back light from the light emitting source to the monitoring means.   5. The optical scanning device according to claim 4, wherein the monitor reflecting means is formed integrally with the frame substrate.   An image forming apparatus comprising the optical scanning device according to claim 1.

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