JPH09211251A - Fiber positioning structure in scanning optics - Google Patents

Abstract

(57) Abstract: It is an object of the present invention to provide a fiber positioning structure capable of positioning a fiber at low cost and with high accuracy. SOLUTION: The flat plate (139) and the adhesive surface (136) facing the flat plate have the same number of V grooves (13) as the fibers (120).
7) is provided in parallel, and the hardness of the base member is set smaller than that of the flat plate and the fiber. Further, the fiber is sandwiched between the V groove and the flat plate, and the flat plate and the bonding surface are adhered to each other, whereby the V groove is deformed and the fiber is positioned along the flat plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning optical device for scanning a light beam in a laser printer or the like, and more particularly to a multi-beam scanning optical device for simultaneously scanning a plurality of light beams.

[0002]

2. Description of the Related Art Conventionally, in a scanning optical device used for a laser printer or the like, a multi-beam scanning optical device for simultaneously scanning a plurality of light beams is known. In the multi-beam scanning optical device, it is necessary to form a plurality of point light sources that are close to each other as object points in order to form a plurality of beam spots on the surface to be scanned at minute intervals. As a light source for forming a plurality of point light sources close to each other, a type using a monolithic multi-point light emitting semiconductor laser has been conventionally known. However, the number of light emitting points obtained by the monolithic semiconductor laser is 2-3 at the current product level, and the number of scanning lines formed in one scanning is set to 4 or more in order to improve the processing speed. Is difficult.

Therefore, as a light source for forming a plurality of point light sources close to each other, a scanning optical device has been proposed in which light fluxes from a plurality of independent semiconductor lasers are brought close to each other by using optical fibers. In this case, by aligning the exit ends of multiple optical fibers,
It is possible to form a large number of adjacent point light sources.

In an optical fiber, the part of the core that actually transmits light is several microns, and the periphery of the core is covered with a cladding of several tens of microns. Therefore, when the exit end face of the optical fiber is aligned in the sub-scanning direction, a gap is formed between the beam spots formed on the image plane by the light beam formed by the optical fiber. Therefore,
The exit end face of the optical fiber needs to be aligned so as to be largely inclined in the main scanning direction.

At this time, if the exit end faces of the optical fibers are not aligned on a straight line and vary, the beam spot will be largely displaced in the sub-scanning direction on the image plane. Therefore, the exit end surface of the optical fiber needs to be positioned so as to be aligned on a straight line with high accuracy. Therefore, a technique has been studied in which a V-groove is processed with high precision in a block made of a material such as glass or ceramics having a large hardness and hardly deformed, and an optical fiber arranged in the V-groove is pressed by a flat plate.

[0006]

However, in order to form a highly accurate V groove, a material having a high hardness such as glass or ceramics must be highly accurately ground, which is costly and not suitable for mass production. There was a problem.

An object of the present invention is to provide a fiber positioning structure capable of positioning a fiber at low cost and with high accuracy.

[0008]

In order to solve the above-mentioned problems, a fiber positioning structure in a scanning optical device according to a first aspect of the present invention is a flat plate and a V-groove having the same number of fibers as the number of fibers on an adhesive surface facing the flat plate. The base member has a hardness lower than that of the flat plate and the fiber, and the plurality of fibers are sandwiched between the V groove and the flat plate, and the flat plate and the bonding surface are bonded to each other, whereby the groove is deformed. , The fibers are positioned along a flat plate. With this configuration, even if the V-groove processing accuracy varies to some extent,
Since the optical fiber bites into the V groove due to the elastic deformation of the V groove, the optical fiber can be positioned along the smooth surface of the flat plate.

The V groove can be formed so that adjacent optical fibers do not come into contact with each other. Further, the bonding surface may be located on both sides of the V groove in the width direction of the V groove. Further, a gap larger than the outer diameter of the optical fiber can be provided in the base member adjacent to the V groove in the longitudinal direction of the V groove.

Further, in the fiber positioning structure of the scanning optical device according to the present invention, a flat plate and an adhesive surface facing the flat plate are provided with a U-shaped groove in which a plurality of optical fibers can be juxtaposed. The flat plate has a lower hardness than the base member and the fibers, and the plurality of fibers are sandwiched by the U-shaped groove and the flat plate, and the flat plate is deformed by bonding the bonding surface to the flat plate. It is also possible that the fibers are positioned along the bottom surface of the U-shaped groove. With this configuration, the optical fiber bites into the flat plate due to elastic deformation of the flat plate, and thus the optical fiber can be positioned along the bottom surface of the U-shaped groove.

It should be noted that the adhesive surface may be located on both sides of the U-shaped groove in the width direction of the groove. Further, a gap larger than the outer diameter of the optical fiber can be provided in the base member adjacent to the U-shaped groove in the longitudinal direction of the groove.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a fiber positioning structure in a scanning optical device according to the present invention will be described below. The scanning optical device shown as the embodiment scans eight laser beams at the same time, thereby performing eight scans in one scan.
It is a multi-beam scanning optical device that simultaneously forms scanning lines of a book. First, the schematic configuration of the entire apparatus will be described.

FIG. 1 is a perspective view showing a scanning optical device according to this embodiment, and FIG. 2 is a side view showing the scanning optical device together with a photosensitive drum. As shown in FIG. 1, the scanning optical device is configured by arranging a scanning optical system in a flat casing 1 having a substantially rectangular parallelepiped shape. The upper opening of the casing 1 is closed by the upper lid 2 when in use.

At the upper part of the casing 1 in the figure, a connector section 102 for receiving signals relating to image information is provided. A laser block support substrate 300 is provided adjacent to the connector 102. The support substrate 300 holds eight semiconductor lasers 101 that emit a light beam based on an image signal and an incident end face of an optical fiber 120 facing each other and described later. 310 (not shown) is fixed. Thereby, the luminous flux is guided to the eight optical fibers 120.

The end face 120 on the exit side of the optical fiber 120
b is held by the fiber alignment block 130. The light flux from the exit end face 120b is a collimator lens 140, a half mirror 144, a dynamic prism 160, and the cylindrical lens 1 described later.
The light enters the polygon mirror 180 via 70. The polygon mirror 180 is rotationally driven by a polygon motor 371 (see FIG. 2) fixed to the casing,
It reflects and deflects the light flux that has entered the mirror surface. The light beam deflected by the polygon mirror 180 is imaged on a predetermined image forming surface by the fθ lens 190 which is an image forming lens, reflected by the folding mirror 200 downward in the drawing, and is scanned as shown in FIG. The surface is guided onto the photosensitive drum 210.

Here, in order to define the operation of the optical element,
The fθ lens 190 and the photosensitive drum 2 are arranged in a plane perpendicular to the optical axis.
A direction corresponding to the scanning direction of the light flux on 10 is defined as a main scanning direction, and a direction orthogonal to the main scanning direction in a plane perpendicular to the optical axis is defined as a sub scanning direction. Also, in the figure, the fθ lens 19
An X axis parallel to the optical axis of 0, a Y axis and a Z axis orthogonal to each other in a plane perpendicular to the X axis are defined. The Y axis and the Z axis correspond to the main scanning direction and the sub scanning direction, respectively.

Next, each component of the optical system will be described with reference to FIG. 3 showing the outline of the optical system of the above-mentioned apparatus. The light source unit 100 includes eight semiconductor lasers 101, eight optical fibers 120 that transmit divergent light beams emitted from these semiconductor lasers, and a fiber alignment block 1 that aligns these optical fibers 120 in a straight line.
30. The optical fiber 120 is a silica glass fiber having a core diameter of 6 μm and an overall diameter including the cladding of 125 μm.

The end of the optical fiber 120 including the incident end face 120a is held by a fiber support 319 which is a support tube. The fiber support 319 is held by the laser block 310 with the incident end face 120a and the semiconductor laser 101 facing each other. Then, the light flux emitted from the semiconductor laser 101 is transmitted through the optical fiber 12
The light enters the incident end face 120a of 0.

As shown in FIG. 3, in the optical path between the light source section 100 and the polygon mirror 180, the collimating lens 140 and the collimating lens 140 which make the divergent light beam emitted from the exit end face of the optical fiber into a parallel light beam are emitted. The slit 142 for controlling the beam diameters of the light beam in the main scanning direction and the sub-scanning direction, the half mirror 144 for separating the light beam transmitted through the slit 142 into two, and the angle of the light beam reflected by the half mirror 144 in the sub-scanning direction are rotated. The dynamic prism 160 that is sequentially controlled by doing so, and the cylindrical lens 170 that converges the light beam whose angle is controlled by the dynamic prism 160 in the sub-scanning direction are provided.

The light flux transmitted through the half mirror 144 is incident on an APC (Automatic Power Control) signal detecting section 150 which detects a light quantity and obtains a signal for controlling the output of the semiconductor laser. The APC signal detection unit 150 converges the light flux that has passed through the half mirror 144 by the condenser lens 151 and makes it enter the polarization beam splitter 153. Polarizing beam splitter 1
Reference numeral 53 separates the incident light flux into transmitted light that transmits in the incident direction and polarized light that is polarized in a direction orthogonal to the incident direction. The transmitted light is detected by the APC first light receiving element 157, and the polarized light is detected by the APC second light receiving element 155.

The exit end face 120b of the fiber 120 is
A fiber alignment block 130 and a fiber alignment block holder 300 (not shown) described later.
Thus, as shown in FIG. 4, they are arranged at predetermined intervals on a straight line inclined by a predetermined angle with respect to the main scanning direction. The eight point light sources arranged in this way, that is, the light flux from the point light source array, is transmitted through the collimator lens 140, the cylindrical lens 170, and the like in FIG.
An image is formed in the sub-scanning direction in the vicinity of the mirror surface. The incident light flux on the polygon mirror 180 is scanned in the Y direction by the rotation of the polygon mirror 180 and is incident on the fθ lens 190.

The fθ lens 190 is a polygon mirror 18
From the 0 side to the folding mirror 200 side, negative, positive, and positive in the main scanning direction and the sub scanning direction, respectively.
It comprises first, second, third, and fourth lenses 191, 193, 195, and 197 having positive and negative powers.
The light flux transmitted through the fθ lens 190 is reflected by the folding mirror 2
An image is formed on the surface of the photoconductor drum 210 (FIG. 2) via 00, and the scanning speed in the main scanning direction becomes constant. With such a configuration, eight beam spots are formed on the image forming surface of the photosensitive drum 210 as shown in FIG. 5, and one scan makes eight scans close to each other in the sub-scanning direction. A line is formed.

Next, an embodiment of the fiber positioning structure according to the present invention will be described. Optical fiber 120
A fiber alignment block 130 is provided in order to arrange the emitting end faces 120b on a straight line. FIG.
6A and 6B are a plan view and a front view showing the fiber alignment block 130, and FIG. 7 is an exploded perspective view. As shown in FIG. 7, the fiber alignment block 130 is a base 131 that is a plate-shaped block.
And a pressing plate 139, which is a flat plate, are stacked and adhered.

The holding plate 139 is a rectangular flat plate made of the same quartz glass as the optical fiber 120, and has a smooth surface. On the other hand, the base 131 is a substantially rectangular plate-shaped block having a hardness smaller than that of the holding plate 139 and the optical fiber 120 and formed of a material such as resin.

The base 131 has a predetermined length in a range from one end surface 131a in the longitudinal direction of the base 131.
A step is formed so that the height from the lower surface 131b is increased. This step is formed larger than the outer diameter of the optical fiber 120. In the base 131, a high-height portion serves as an alignment portion 133 that positions the optical fiber 120, and the stepped portion is the optical fiber 120.
Introduction part 135 for introducing the alignment part 133 into the alignment part 133
Becomes

Eight V grooves 137 extending in the longitudinal direction of the base 131 are formed in the center of the base 131 in the width direction on the upper surface of the alignment portion 133. Also,
The upper surface of the V-groove 137 of the alignment portion 133 on both sides in the base width direction is an adhesive surface 136. As shown in FIG. 6 (a), each optical fiber 120 has an exit end face 120 b.
Are aligned with the V-groove 137 in a state in which they are substantially aligned with the end surface 131a. As shown in FIG. 6B, the V groove 137 is formed so that the upper portion of the optical fiber 120 projects upward from the V groove 137 by a predetermined amount.

The optical fibers 12 arranged in the V groove 137.
0 is pressed by the pressing plate 139, and a low-viscosity liquid adhesive is poured between the bonding surface 136 of the base 131 and the pressing plate 139 to bond the bonding surface 136 and the pressing plate 139 to each optical fiber 120.
Is sandwiched between the pressing plate 139 and the V groove 137.

Since the pressing plate 139 has a large hardness and the base 131 has a small hardness, pressing the optical fibers 120 arranged in the V groove 137 with the pressing plate 139 causes the V groove 137 to have some variation in processing accuracy. , The V groove 137 is elastically deformed and the optical fiber 120 is V-shaped.
Cut into the groove 137. Therefore, the optical fibers 120 can be arranged with high precision along the smooth surface of the pressing plate 139. That is, the emission end faces 120b can be aligned on a straight line with high accuracy, and a linear array of point light sources can be obtained.

The base 131 of the optical fiber 120
Position in the horizontal direction with respect to (ie, adjacent optical fiber 1
The interval (20 intervals) is determined by the optical fiber 120 evenly hitting both surfaces of the V groove 137 and elastically deforming both surfaces evenly. Therefore, the adjacent optical fibers 12
If 0s contact each other, the optical fibers 120 may not evenly contact both surfaces of the V groove 137. Therefore, V groove 1
The shape of 37 is formed so that there is a slight gap between adjacent optical fibers 120.

As described above, according to the present embodiment, the position in the height direction with respect to the base 131 of the optical fiber 120 is determined by the smooth surface of the holding plate 139, so that the exit end surface 120b of the optical fiber 120 is highly accurate. Will be aligned on a straight line. Although the surface of the pressing plate 139 needs to be processed to be smooth, even if the pressing plate 139 having high hardness is used,
High-precision machining of a flat surface is extremely easy as compared with high-precision machining of V-grooves, so that the machining cost is low.

Further, the base 131 of the optical fiber 120
Horizontal position with respect to (ie adjacent optical fiber 1
Since the interval of 20) is determined by the size of the V groove 137, it is affected by the processing variation of the V groove 137. However,
As can be seen from FIG. 4, the inclination of the point light source array including the aligned emission end faces 120b with respect to the main scanning direction is about 5 degrees, so that the variation in the interval between the adjacent optical fibers 120 is less of a problem than the linearity.

The introduction unit 135 is the alignment unit 13
Since there is a predetermined amount of step difference with respect to 3, there is a predetermined clearance between the introduction portion 135 and the pressing plate 139 when the pressing plate 139 and the base 131 are bonded. This clearance is set to be larger than the outer diameter of the optical fiber 120. The optical fiber 120 whose tip is sandwiched between the pressing plate 139 and the V groove 137 is reliably fixed by pouring an adhesive into this clearance.

Further, instead of the eight V-grooves 137, the structure shown in FIG.
It is also possible to form one U-shaped groove 138 as shown in FIG. In this case, the U-shaped groove 138 has a width that allows the plurality of optical fibers 120 to be arranged with their axes parallel to each other. The hardness of the holding plate 139 is set to be smaller than that of the optical fiber 120 or the base 131. Here, the base 131 is connected to the optical fiber 12
The same quartz glass as 0 is used, and the holding plate 139 is made of resin.
Further, the U-shaped groove 138 is processed to have smooth bottom and side surfaces.

The plurality of optical fibers 120 arranged in the U-shaped groove 138 are pressed by the pressing plate 139, and the bonding surface 136 and the pressing plate 139 are bonded to each other, whereby the optical fibers 120 are connected to each other. It is arranged in the groove 138 in this state. Therefore, when the U-shaped groove 138 is used, the position of the optical fiber 120 in the base height direction is the groove 1 as in the case of the V groove 137.
Since it is determined by the bottom surface of 38, the optical fiber 120 is aligned with high precision in a straight line.

Next, a structure for setting the inclination angle of the fiber alignment block 130 holding the optical fiber 120 will be described. As shown in FIG. 3, the fiber alignment block 130 includes the collimator lens 1
It is held in the state of facing the optical axis X in front of 40. A fiber alignment block holder that holds the fiber alignment block 130 rotatably around the optical axis (X axis) in order to adjust the tilt angle of the point light source array composed of the exit ends 120b of the aligned optical fibers 120 with respect to the main scanning direction. 330 (not shown in FIG. 3) is provided. FIG. 9 shows the fiber alignment block holder 330.

As shown in FIG. 9, the fiber alignment block holder 330 has an L-shaped base 320, which is an L-shaped mount, and a fiber alignment block 13.
A cylindrical member 331 for holding 0 is provided.

The cylindrical member 331 has a cylindrical body 331a and an attachment portion 333 attached to one end of the cylindrical body 331a. The mounting portion 333 is an L-shaped plate member, and includes a vertical portion 333a fixed to the end surface of the cylindrical body 331a by adhesion and a horizontal portion 333b extending from the end surface in parallel with the longitudinal direction of the cylindrical member 331. ing.

The L-shaped base 320 has contact surfaces provided in two directions orthogonal to each other. Then, the cylindrical member 331 is clamped by the fixing plate 335 so that the outer periphery of the cylindrical body 331a contacts the two contact surfaces.
In this way, the cylindrical member 331 is rotatably held with the center of the cylindrical body 331a as the rotation axis. Further, in the plane orthogonal to the rotation axis, the position is regulated by the two orthogonal contact surfaces of the L-shaped base 320. The cylindrical member 331
Is rotated with the fixing plate 335 loosened.

Fiber alignment block 130
Is fixed to the horizontal portion 333b of the mounting portion 333 by adhesion. Fiber alignment block holder 33
0 is configured such that when the fiber alignment block 130 is fixed to the horizontal portion 333b, a straight line connecting the centers of the exit end faces 120b of the optical fibers 120 held by the fiber alignment block 130 passes through the rotation axis of the cylindrical member 331. ing. Further, the fiber alignment block 130 is fixed to the mounting portion 333 such that the center of the point light source array is aligned with the rotation axis of the cylindrical member 331. Therefore, by rotating and adjusting the cylindrical member 331, the fiber alignment block 130 is rotated around the center of the point light source array. The cylindrical member 331
A collimator lens 140 is attached near the end opposite to the attachment portion 333, and when the cylindrical member 331 is rotationally adjusted, the collimator lens 140 also rotates together.

As described above, according to the fiber positioning structure of this embodiment, the optical fiber 120 bites into the V groove 137 due to the elastic deformation of the V groove 137 even if the processing accuracy of the V groove 137 varies to some extent. The 120 can be arranged with high precision along the smooth surface of the pressing plate 139. That is, the optical fibers 120 can be aligned on a straight line with high accuracy. Further, since a certain degree of variation in the processing accuracy of the V groove 137 is allowed, the manufacturing cost can be reduced.

Further, instead of the eight V-shaped grooves 137, one U-shaped groove 138 is used, and the hardness of the holding plate 139 is based on the base 1
If it is smaller than 31 or optical fiber 130,
Since the optical fiber 120 bites into the holding plate 139 due to the elastic deformation of the holding plate 139, the optical fiber 120 can be positioned along the bottom surface of the U-shaped groove 138.

[0042]

As described above, according to the optical fiber positioning structure of the first aspect of the present invention, even if the machining accuracy of the V groove varies to some extent, the optical fiber bites into the V groove due to the elastic deformation of the V groove. The grooves can be arranged with high precision along the smooth surface of the pressing plate. Further, since the V-groove processing accuracy is allowed to vary to some extent, the manufacturing cost can be reduced. According to the optical fiber positioning structure of the second aspect of the invention, the optical fiber bites into the flat plate due to the elastic deformation of the flat plate, so that the optical fiber can be positioned along the bottom surface of the U-shaped groove.

[Brief description of drawings]

FIG. 1 is a perspective view showing a scanning optical device according to an embodiment of a fiber positioning structure of the present invention.

FIG. 2 is a side view of the scanning optical device of FIG.

3 is a diagram showing an optical system of the scanning optical device of FIG.

FIG. 4 is a diagram showing an arrangement of exit ends of fibers.

FIG. 5 is a diagram showing a beam spot on an image plane.

FIG. 6 is a plan view and a front view showing an embodiment of a fiber positioning structure of the present invention.

FIG. 7 is a perspective view showing the fiber alignment block in FIG.

FIG. 8 is a front view showing another embodiment of the fiber positioning structure of the present invention.

9 is a perspective view showing a fiber alignment block holder for fixing the fiber alignment block in FIG.

[Explanation of symbols]

 1 Casing 2 Lid 100 100 Light Source 120 Fiber 120b Emitting End Face 130 Fiber Alignment Block 131 Base 133 Alignment 135 135 Introducing 137 V Groove 138 C-shaped Groove 139 Holding Plate 140 Collimating Lens 180 Polygon Mirror 320 L-shaped Base 330 Fiber Alignment Block Holder 331 Cylindrical member 333 Mounting part 335 Fixed plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsunori Iima 2-36-9 Maeno-cho, Itabashi-ku, Tokyo Asahi Kogaku Kogyo Co., Ltd.

Claims (7)

[Claims] 1. A scanning optical device in which a plurality of point light sources are formed by a plurality of optical fibers for transmitting a light beam, and a light flux from each point light source is simultaneously scanned, for positioning the optical fibers. And a base member in which the same number of V grooves as the optical fibers are arranged in parallel on the adhesive surface facing the flat plate, the base member having a hardness smaller than that of the flat plate and the optical fiber, and the V groove and the flat plate. A fiber in a scanning optical device, characterized in that the groove is deformed and the optical fiber is positioned along the flat plate by sandwiching the plurality of optical fibers by and bonding the flat plate and the bonding surface. Positioning structure. 2. The fiber positioning structure in a scanning optical device according to claim 1, wherein the V groove is formed so that the adjacent optical fibers do not come into contact with each other. 3. The bonding surface is located on both sides in the width direction of the V groove with respect to the V groove.
A fiber positioning structure in the scanning optical device according to. 4. The base member is adjacent to the V groove in the longitudinal direction of the V groove and has a gap larger than the outer diameter of the optical fiber.
A fiber positioning structure in the scanning optical device according to any one of 1. 5. A scanning optical device for forming a plurality of point light sources by a plurality of optical fibers for transmitting a light beam, and simultaneously scanning light fluxes from the respective point light sources, for positioning the optical fibers. And a base member having a U-shaped groove in which the plurality of optical fibers can be juxtaposed on the adhesive surface facing the flat plate, and the flat plate has a hardness smaller than that of the base member and the optical fiber. While sandwiching the plurality of fibers by the U-shaped groove and the flat plate, by bonding the flat plate and the bonding surface, the flat plate is deformed, the optical fiber along the bottom surface of the U-shaped groove A fiber positioning structure in a scanning optics characterized by being positioned. 6. The fiber positioning structure in a scanning optical device according to claim 5, wherein the bonding surface is located on both sides of the U-shaped groove in the width direction of the groove. 7. The base member is adjacent to the U-shaped groove in the longitudinal direction of the groove and has a gap larger than the outer diameter of the optical fiber. A fiber positioning structure in the described scanning optics.