JP2002090673A - Optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanner, driven with a low torque at high- velocity revolution, of which the power consumption and the noise are suppressed, the productivity is improved, and which accommodates to forming an image of high quality. SOLUTION: The optical scanner is provided with a light source and a deflection means, which deflects and repeatedly scans the light beam emitted from the light source. The deflection means of the optical scanner is provided with a light-transmissive disk member whose outer side face is cylindrical and the inner side face forms reflecting faces of a polygonal column, which is coaxial with the center of the cylinder, and a flat plate-shaped optical transmitting member, having a cylindrical hole in which the disk member is inserted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical scanning device,
In particular, the present invention relates to an optical scanning device used in a writing system such as a digital copying machine and a laser printer.

[0002]

2. Description of the Related Art In a conventional optical scanning apparatus, a rotating polygon mirror having each side of a polygonal prism as a reflecting surface is used. It is known that the rotating polygon mirror increases the air resistance at each corner of the polygonal prism as the rotation speed increases, which causes noise and uneven rotation speed. As a countermeasure for this, as disclosed in Japanese Patent Application Laid-Open No. 4-62513, it has been proposed to provide a cylindrical body having a transparent body provided so as to cover each mirror surface of a polygon mirror to reduce air resistance. Japanese Patent Application Laid-Open No. H11-174363 discloses an example in which a configuration in which a polygonal column concave portion is formed in the center of a cylindrical body is integrated by resin molding.

[0003]

In general, a rotary polygon mirror merely functions to change the direction of an incident beam. When a parallel light beam is incident, it is emitted as a parallel light beam, so that the beam diameter incident on the imaging lens is uniform. It is. The air resistance can be reduced by providing a cylindrical transparent body on the surface of the reflecting surface as in any of the conventional examples described above, but the transparent body itself,
Since a parallel light beam is incident on the lens because it is equal to a lens having power in the main scanning direction, the emitted beam becomes a focused light beam. For this reason, there is a problem that the diameter of the beam incident on the imaging lens varies depending on the scanning angle and is difficult to handle.

The present invention has been made to solve this problem, and can be driven with low torque even by high-speed rotation, can suppress power consumption and noise, can improve production efficiency, and can produce high-quality images. It is an object of the present invention to provide an optical scanning device capable of coping with the formation.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a deflection device in an optical scanning device according to the present invention has a light source and a deflection means for deflecting and repeatedly scanning a light beam from the light source. The means has a light-transmitting disk member formed by forming an outer surface with a cylindrical surface and an inner surface with a reflecting surface of a polygonal prism concentric with the center of the cylindrical surface, and a cylindrical hole into which the disk member is inserted. It is characterized by having a flat optical transmission member. Therefore, since the light beam from the light emitting source propagates in the same medium when passing through the cylindrical surface of the disk member, the light beam does not converge and the state before and after the deflection is changed. An optical scanning device which can be maintained and has good image forming performance can be provided. In addition, since the disk member is not exposed, the air resistance during rotation is small, and power consumption and generation of noise can be suppressed.

Further, by providing the deflecting means with a laminated structure of a plurality of layers, it is possible to provide an optical scanning device for simultaneously scanning a plurality of lines, enabling high-speed recording without increasing the rotation speed of the disk member, and reducing power consumption and noise. Occurrence can be suppressed.

Further, since the reflecting surface of the polygonal column of the disk member is formed of a metal coating, the weight can be reduced as compared with the case where a cylindrical portion is provided outside the solid polygon mirror, and the load during rotation is reduced. Power consumption can be reduced.

Also, at least one of the bottom surfaces of the disk member is formed with spiral radial irregularities in the circumferential direction, so that
Since the air bearing can be formed between the outer surface of the disk member and the inner surface of the cylindrical hole into which the disk member is inserted, there is no need to use a separate bearing means, the number of parts can be reduced, and the weight can be reduced.

Furthermore, since the unevenness is formed by the same metal film as the reflection surface, the film can be formed at the same time, so that the manufacturing process can be simplified and the production efficiency can be improved.

Further, by providing a beam incident means for causing a light beam from a light emitting source to enter from the surface of the optical transmission member, only the deflecting section can be configured independently, and the selection range of the semiconductor laser is expanded, so that versatility is enhanced. Production efficiency can be improved. When optical waveguide plates are stacked, incident beams corresponding to the respective layers can be coaxially incident.

Further, the light transmitting member forms an exit end of the light beam deflected by the deflecting means from the light transmitting member in a non-linear manner in the main scanning direction, and sets the exit position to the scanning surface and the magnification of the scanning lens. Since they are set in accordance with each other, the optically conjugate relationship is maintained at any of the scanning angles, the imaging performance is improved, and high-quality image formation can be performed.

Further, the light transmitting member is provided with beam emitting means for emitting the light beam deflected by the deflecting means from the surface of the light transmitting member, so that the light beam emitted from the end face is flat in the sub-scanning direction. In comparison with the above, since a predetermined light beam diameter can be secured, a beam spot on the surface to be scanned can be narrowed down more, and high-quality image formation can be performed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical scanning device according to the present invention has a light emitting source and a deflecting means for deflecting a light beam from the light emitting source to repeatedly scan the light beam. The deflecting means includes a light-transmitting disk member having an outer surface formed by a cylindrical surface and an inner surface formed by a reflecting surface of a polygonal column concentric with the center of the cylindrical surface, and a cylinder into which the disk member is inserted. And a flat optical transmission member having a hole.

[0014]

FIG. 1 is a perspective view showing the configuration of an optical scanning device according to a first embodiment of the present invention, and FIG. 2 is a schematic sectional view showing the configuration of the optical scanning device of the present embodiment. FIG. 3 shows FIG.
FIG. 4 is a diagram showing a state of propagation of a light beam in a disk member 106 of FIG. FIG. 4 is a view showing the configuration of the disk member 106 shown in FIG. 1 and 2, an optical waveguide plate 101 made of a dielectric such as LiNbO ₃ having a thickness of about several hundred μm is mounted on a ceramic substrate 102 on which a lead frame 103 is formed. End face 101-1 of optical waveguide plate 101
Is provided with a semiconductor laser chip 104 for emitting a light beam inside the optical waveguide plate 101. The distributed index lens 105 is a lens that converts the light beam from the semiconductor laser chip 104 into a parallel light beam. In the optical waveguide plate 101, the light beam propagates as a parallel light beam in the main scanning direction, but propagates in the sub-scanning direction while repeating total reflection at the optical waveguide plate boundary. A disk member 106 made of the same material as the optical waveguide plate 101 having a cylindrical hole at the outer periphery of the cylindrical hole 101-2 formed in the optical waveguide plate 101 and having a square hole formed at the center thereof at the center thereof is rotatable. Is inserted in the state of. The clearance 125 between the inner diameter of the cylindrical hole 101-2 and the outer diameter of the cylindrical portion of the disk member 106 is about several μm, and the light beam from the semiconductor laser chip 104 passes through the clearance 125 from the optical waveguide plate 101 and enters the disk member 106. Propagation, and is reflected and deflected by the inner surface of the square hole, and the clearance 12
The light is propagated through the optical waveguide plate 101 through the optical waveguide 5. The propagated light beam is emitted as a divergent light beam in the sub-scanning direction by the diffraction grating 107 having an arc-shaped groove formed on the surface of the optical waveguide plate 101. The emitted light beam is scanned by the scanning lens 108.
Thus, an image is formed on the surface S to be scanned and scanned, thereby performing image recording.

Here, the apparent center O of the divergence angle from the diffraction grating 107 is optically conjugate to the surface to be scanned, so that the same line is scanned even if the emission direction of the light beam fluctuates in the sub-scanning direction. I am trying to do it. As a means for emitting a light beam from the optical waveguide plate, in addition to the above-described method using a diffraction grating, a prism may be provided on the upper surface, or the like.

The disk member 106 has a rotor portion laminated on the Si substrate 114 as shown in FIG. The Ni substrate is formed by laminating an Ni thin film on the Si substrate 114 with the electrode pattern 115 as shown in FIG. 1 on the lower surface and the spiral radial uneven pattern 116 on the upper surface. Also, a spiral radial uneven pattern 120 is formed on the lower surface of the disk member 106, and at the same time, as shown in FIG. 3, a Ni coating 121 is formed on the inner side surface of the square hole to make the inside of the disk member 106 a reflection surface. . In the present embodiment, a Ni coating is formed on portions other than the spiral radial uneven patterns 116 and 120 to form convex portions. A plurality of opposing electrodes 109 are mounted on the upper surface of the optical waveguide plate 101 as shown in FIG.
An electrostatic motor is configured with the electrode pattern 115, and the disk member 106 is rotated by sequentially switching the voltage application to the counter electrode 109. As shown in FIG. 2, the rotor portion is sealed with a ceramic cover 110 similarly to the above-described ceramic substrate 102, and has a spiral radial pattern formed by rotation and a pumping action from the center portion to the outer peripheral surface. The outside air pressure is increased,
The posture can be maintained in a non-contact state.

Further, as shown in FIG.
7, a drive circuit for modulating the semiconductor laser 104 is formed, and a drive circuit for controlling voltage switching to an electrode pattern is mounted on the bare chip 118. As shown in FIG. 2, it is mounted on a ceramic substrate 102 in the same manner as the optical waveguide plate 101, sealed with a cover 110, and provided with a glass window 119 at the light beam emission port, in the same manner as the hybrid IC. Packaging. The scanning beam is detected by the light detection sensor 113 by the mirrors 111 and 112 on the scanning start side, and timing for starting image writing is set. Further, the mirrors 122 and 1 on the scanning end side
The scanning time from the light detection sensor 113 is detected by the light detection sensor 124 and the switching speed is controlled by the drive circuit 118 so that the scanning time is constant.

FIG. 5 is a perspective view showing the configuration of an optical scanning device according to a second embodiment of the present invention. In the same figure, in the optical scanning device of this embodiment, three optical waveguide plates 201 to 203 are laminated. Semiconductor laser chip 2 provided for each layer
The coupling lenses 04 to 206 and the coupling lenses 207 to 209 are incident from the outside of the package through the prisms 210 to 212 having substantially the same refractive index as the optical waveguide plate at a predetermined angle θc and an angle smaller than the critical angle of the optical waveguide plate. . Each semiconductor laser is arranged coaxially toward the deflector, and the angle of incidence on each reflection surface and the reflection point are the same. Disc member 213
215 are also laminated so as to face the respective layers of the optical waveguide plates 201 to 203, and the light beams from the respective semiconductor laser chips 204 to 206 are propagated in the same manner as in the first embodiment,
Scanned. Naturally, a thin film is formed between the layers so that a light beam having a critical angle or less is not emitted from the boundary.

FIG. 6 is a schematic sectional view showing the structure of the optical scanning device according to the second embodiment. The disk members 213 to 215 are made of Si
A rotor portion is formed by being laminated on the substrate 216, and a spiral radial concavo-convex pattern is similarly formed on the upper surface and the lower surface of the lowermost disk member 215. The laminated disk members 213 to 215 have holes 201-penetrating through the respective layers of the optical waveguide plates 201 to 203 with the Si substrate 216 side facing upward.
1 and each layer is arranged so as to face each other. A hole is formed in the center of the Si substrate 216, and S
The pole and the N pole are magnetized, and a tubular magnet 217 circumscribing the square hole is joined. Optical waveguide plates 201 to 203
A plurality of thin-film coils 219 are buried along the outer edge of the hole 201-1 in the ceramic substrate 218 on which is mounted. Disc member 213
215 rotate. As shown in FIG.
A drive circuit for controlling the current of each coil is formed on the coil 21 and mounted on the ceramic substrate 218. The rotor portion is sealed with a ceramic cover 220 as in the first embodiment, and can maintain a posture in a non-contact state by a pumping action on an outer peripheral surface by a spiral radial pattern by rotation. The light beams scanned by the disk members 213 to 215 are emitted radially in the sub-scanning direction from the end faces of the optical waveguide plates 201 to 203, and are imaged on the surface to be scanned by the scanning lens 221 at intervals of P. In this embodiment, the deviation of the imaging position in the sub-scanning direction is reduced by making the radiation center and the surface to be scanned optically conjugate.
The exit end faces of the optical waveguide plates 201 to 203 are formed in a curved shape in the main scanning direction in order to adjust the exit position so that the above-mentioned conjugate relationship is maintained at any passing position of the scanning lens. Here, the interval P is designed to be equal to the interval between adjacent lines corresponding to the recording density, and three lines can be recorded simultaneously. The light detection sensors 222 and 223 detect the scanning beams on the scanning start side and the scanning end side.

In this embodiment, the rotor is held by an air bearing by dynamic pressure, but the same effect can be obtained by using another bearing system. In addition, the reflection surface at the center of the disk member is a quadrangle, but the same applies to any polygon. In addition, the outer surface of a solid polygonal pillar may be a cylindrical surface made of a transparent member without having to be hollow.

Further, the present invention is not limited to the above embodiment, and needless to say, various modifications and substitutions can be made within the scope of the claims.

[0022]

As described above, the deflecting means in the optical scanning device according to the present invention, which has the light emitting source and the deflecting means for deflecting the light beam from the light emitting source and repeatedly scanning, has a cylindrical outer surface. A light-transmissive disk member formed by a surface and an inner surface formed by a reflection surface of a polygonal column concentric with the center of the cylindrical surface, and a flat optical transmission member having a cylindrical hole into which the disk member is inserted. It is characterized by having. Therefore, since the light beam from the light emitting source propagates in the same medium when passing through the cylindrical surface of the disk member, the light beam does not converge and the state before and after the deflection is changed. An optical scanning device which can be maintained and has good image forming performance can be provided.
In addition, since the disk member is not exposed, the air resistance during rotation is small, and power consumption and generation of noise can be suppressed.

In addition, since the deflecting means has a laminated structure of a plurality of layers, an optical scanning device for simultaneously scanning a plurality of lines can be provided, and high-speed recording can be performed without increasing the rotation speed of the disk member, thereby reducing power consumption and noise. Occurrence can be suppressed.

Further, since the reflecting surface of the polygonal prism of the disk member is formed of a metal coating, the weight can be reduced as compared with the case where a cylindrical portion is provided outside the solid polygon mirror, and the load during rotation is reduced. Power consumption can be reduced.

Also, at least one of the bottom surfaces of the disk member is formed with spiral radial irregularities in the circumferential direction, so that
Since the air bearing can be formed between the outer surface of the disk member and the inner surface of the cylindrical hole into which the disk member is inserted, there is no need to use a separate bearing means, the number of parts can be reduced, and the weight can be reduced.

Further, since the unevenness is formed by the same metal film as the reflection surface, the film can be formed at the same time, so that the manufacturing process can be simplified and the production efficiency can be improved.

Also, by providing a beam incident means for causing a light beam from a light emitting source to enter from the surface of the optical transmission member, only the deflection section can be configured independently, and the selection range of the semiconductor laser is expanded, so that versatility is enhanced. Production efficiency can be improved. When optical waveguide plates are stacked, incident beams corresponding to the respective layers can be coaxially incident.

Further, the light transmitting member forms the exit end of the light beam deflected by the deflecting means from the light transmitting member in a non-linear manner in the main scanning direction, and sets the exit position to the scanning surface and the magnification of the scanning lens. Since they are set in accordance with each other, the optically conjugate relationship is maintained at any of the scanning angles, the imaging performance is improved, and high-quality image formation can be performed.

Further, the light transmitting member is provided with beam emitting means for emitting the light beam deflected by the deflecting means from the surface of the light transmitting member, so that the light beam emitted from the end face is flat in the sub-scanning direction. In comparison with the above, since a predetermined light beam diameter can be secured, a beam spot on the surface to be scanned can be narrowed down more, and high-quality image formation can be performed.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a configuration of an optical scanning device according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view illustrating a configuration of the optical scanning device according to the first embodiment.

FIG. 3 is a diagram showing a state of propagation of a light beam in a disk member of FIG. 1;

FIG. 4 is a view showing a configuration of a disk member of FIG. 1;

FIG. 5 is a perspective view illustrating a configuration of an optical scanning device according to a second embodiment of the present invention.

FIG. 6 is a schematic sectional view illustrating a configuration of an optical scanning device according to a second embodiment.

[Explanation of symbols]

101; optical waveguide plate, 101-1, end face, 101-2; cylindrical hole, 102; ceramic substrate, 103; lead frame, 104; semiconductor laser chip, 105; distributed refractive index lens, 106; Lattice, 10
8; scanning lens; 109; counter electrode; 110; cover;
111, 112; mirror, 113, 124; light detection sensor, 114; Si substrate, 115; electrode pattern, 11
6, 120; uneven pattern, 117, 118; bare chip, 119; glass window, 121; Ni coating, 122, 1
23; mirror, 125; clearance.

Claims (8)

[Claims] 1. An optical scanning device comprising: a light emitting source; and a deflecting unit that deflects a light beam from the light emitting source and repeatedly scans the light beam. Light having a light-transmitting disk member formed by a polygonal reflecting surface concentric with the center of a cylindrical surface, and a flat optical transmission member having a cylindrical hole into which the disk member is inserted. Scanning device. 2. The optical scanning device according to claim 1, wherein said deflecting means has a laminated structure of a plurality of layers. 3. The optical scanning device according to claim 1, wherein a reflecting surface of the polygonal pillar of the disk member is formed with a metal coating. 4. A spiral radial irregularity is formed in a circumferential direction on at least one bottom surface of said disk member.
The optical scanning device according to any one of the above. 5. The optical scanning device according to claim 4, wherein the unevenness is formed by the same metal film as the reflection surface. 6. The optical scanning device according to claim 1, further comprising a beam incident unit that causes a light beam from the light emitting source to enter from a surface of the optical transmission member. 7. The optical transmission member according to claim 1, wherein an exit end of the light beam deflected by the deflecting means from the optical transmission member is formed in a non-linear manner in the main scanning direction. Optical scanning device. 8. The optical scanning device according to claim 1, wherein the light transmission member includes a beam emitting unit that emits a light beam deflected by the deflecting unit from a surface of the light transmission member.