JP4327484B2 - Lens fixing device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lens fixing device and a manufacturing method thereof, and more particularly to a lens fixing device for fixing a lens to a predetermined position of a housing for an optical module and a manufacturing method thereof.
[0002]
[Prior art]
Conventionally, in the optoelectronic field such as optical communication and optical measurement, a light source such as a semiconductor laser, an electro-optic element in which an optical waveguide is formed on a dielectric crystal such as lithium niobate, and an optical fiber are used using a lens. Optical coupling to each other is performed.
[0003]
Japanese Patent Laid-Open No. 10-260339 discloses a technique for optically coupling a light emitting element and an optical fiber via a condenser lens. In particular, a fixing device for the condenser lens is shown in FIG. An inclined portion 2 is formed in a housing 1 as shown, and a lens holder 4 holding a condenser lens 5 is sandwiched through a fixing member 3. Then, the inclined portion 2 and the fixing member 3 and the fixing member 3 and the lens holder 4 are welded and fixed by the YAG laser light.
[0004]
However, since the lens fixing method as shown in FIG. 1 requires the fixing member 3, the number of parts is increased and the width of the housing is widened, making it difficult to downsize the optical module including the lens. . Moreover, when the number of parts increases, there is a disadvantage that the cost increases.
In addition, as shown in FIG. 1, since the two fixing members 3 are arranged in the space sandwiched between the inclined portions 2 of the housing 1, the direction is inclined with respect to the direction perpendicular to the paper surface of FIG. 1. In particular, there are few degrees of freedom when tilting in the horizontal direction (left and right in the drawing), and there is a limit to adjustment.
Furthermore, when the lens holder 4 is translated in the left-right direction in FIG. 1 to fix the lens, one of the positions of the left and right fixing members 3 is raised and the other is lowered. For this reason, since the left and right forces for holding the lens holder 4 are not located in the same straight line, the lens is caused by thermal expansion of the fixing member, mechanical stress at the inclined portion or the joint between the lens holder 4 and the fixing member 3, and the like. When a force is applied to the holder 4 from the left and right, the lens holder 4 has a problem that it rotates about a rotation axis in a direction perpendicular to the paper surface of FIG.
[0005]
[Problems to be solved by the invention]
The present invention solves the above-described problems, reduces the number of parts when fixing a lens to a predetermined position of a housing for an optical module, can be downsized, and has good workability during assembly. And a method of manufacturing the same.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problem, in the invention according to claim 1, in a lens fixing device for fixing a lens at a predetermined position inside an optical module housing, a lens holder for holding the lens, and the lens holder at least two have, pedestal and the housing, and the pedestal and both the and the lens holder are joined, the boss and the contact portion abuts on the lens holder pedestal having an inclined surface in contact with Are inclined surfaces that are inclined in directions opposite to the inclined surfaces of the respective pedestals in contact with each other, and the inclined surfaces of the lens holder and the inclined surfaces of the pedestal cooperate to perform laser welding of the corresponding contact portion. the irradiation angle of the laser widely secured according to, characterized in that directly irradiation shines in the abutting portion of the laser from該筺body outside.
[0007]
According to the first aspect of the present invention, since the pedestal has the function of the fixed part and the inclined part in FIG. 1, it is not necessary to provide the inclined part in the housing as in the prior art, and the number of parts can be reduced. Moreover, since the position of the pedestal can be set freely, the adjustment range related to the optical axis adjustment is widened.
Further, when the laser is irradiated by the inclined surface of the lens holder and the inclined surface of the pedestal, it is possible to ensure a wide laser irradiation angle, and the workability during welding is significantly improved.
[0008]
According to a second aspect of the present invention, in the lens fixing device according to the first aspect, the pedestal is disposed so as to sandwich the lens holder from a direction perpendicular to the optical axis of the lens.
[0009]
According to the second aspect of the present invention, it is possible to arrange the pedestal so as to sandwich the lens holder from the direction perpendicular to the optical axis and fix the lens even in a place where there is only a narrow arrangement space close to the width of the lens holder. Become. Moreover, since it is possible not only to support from below the lens holder but also to support the holder so that it is suspended from above the lens holder, the lens can be fixedly supported even in a narrower space.
[0010]
According to a third aspect of the present invention, in the lens fixing device according to the first aspect, the pedestal is disposed so as to sandwich the lens holder horizontally and perpendicularly to the optical axis of the lens. .
[0011]
According to the third aspect of the present invention, since the lens is fixed only by the pedestal, the lateral width of the housing is also narrowed, and the overall size of the apparatus can be reduced.
[0012]
According to a fourth aspect of the present invention, in the lens fixing device according to any one of the first to third aspects, the pedestal has a cross-sectional shape of a triangle having the inclined surface on one side.
[0013]
According to the invention of claim 4, when the inclined surface of the pedestal is used for fixing the lens holder, and the vicinity of the apex on the opposite side of the pedestal is used as a part of the joint between the housing and the pedestal, Since the side faces are always facing upward, it is easy to perform the joining work. Especially during laser welding, the welded part is exposed upward, so the laser irradiation angle is wide and reliable joining is possible. Can be easily realized.
[0014]
According to a fifth aspect of the present invention, in a method of manufacturing a lens fixing device for fixing a lens at a predetermined position inside a housing for an optical module, the lens holder that holds the lens and the lens holder are in contact with each other. the pedestal having an inclined surface and having at least two, the two flat surfaces including the respective pedestals abutting contact portion in the lens holder, and an inclined surface which is inclined to the inclined face and opposite direction of each base in contact with, The lens holder is held by the positioning device and positioned at the predetermined position. Next, the inclined surface of the pedestal is brought into contact with the lens holder, and the inclined surface of the lens holder and the inclined surface of the pedestal are by ensuring a wide laser irradiation angle of the laser welding cooperate to laser weld the pedestal and the lens holder by irradiating directly abutting portion of the laser from該筺body outside With, and joined to the pedestal and the housing, then, and cancels the holding of the lens holder by the positioning device.
[0015]
According to the fifth aspect of the present invention, the lens holder is positioned at a predetermined position by the positioning device, and the lens holder is fixed at the predetermined position by the pedestal. Therefore, the degree of freedom of the fixing position of the lens holder with respect to the optical module housing is increased. It is high and is fixed stably by the pedestal, so that the workability at the time of manufacture is high, the mounting accuracy can be improved, and inexpensive and stable optical characteristics (reduction of coupling loss, etc.) are realized. Is possible.
In addition, since the pedestal is brought into contact with the lens holder after the position of the lens holder is determined, the pedestal and the lens holder are arranged in close contact with each other, so that the stability of the lens fixing can be remarkably enhanced.
Moreover, when the laser beam is irradiated by the inclined surface of the lens holder and the inclined surface of the pedestal, a wide laser irradiation angle can be secured, and the workability during welding is greatly improved.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail using preferred examples.
FIG. 2 is a perspective view showing an example of a lens fixing device according to the present invention.
The lens fixing device shown in FIG. 2 includes a lens holder 12 that holds a lens 14 and two pedestals 11 that abut and support one side of the lens holder. The pedestal is in a direction perpendicular to the optical axis of the lens. Is arranged so as to sandwich the lens holder.
At the time of assembling the lens fixing device, the lens holder 12 is supported by the lens positioning device. Specifically, the lens holder is connected to the tip 15 of an arm provided in the lens positioning device that can be moved and adjusted in a three-dimensional direction. It is configured to
The tip of the arm 15 and the lens holder 12 can be connected by a method of providing a means for sandwiching the lens holder at the tip of the arm, or by forming a screw thread at the tip of the arm 15 so that the lens holder side as shown in FIG. There is a method of fixing both by screwing into the provided screw holes.
[0017]
A method for assembling the lens fixing device will be described.
First, the lens holder 12 is attached to the tip of the arm 15 provided in the lens positioning device, and the lens holder is disposed at a predetermined position of the optical module housing.
Next, the lens holder is adjusted to an appropriate position while detecting the light wave that passes through the lens 13 held by the lens holder and detects the light wave emitted from the optical module by a photodetector (not shown).
After the positioning of the lens holder is completed, the two pedestals 11 are brought into contact with the respective sides of the lens holder 12 and placed on the optical module casing. An inclined surface 14 is formed on the pedestal, and the inclined surface is configured to contact the lens holder.
[0018]
After the arrangement of the lens holder and the pedestal is completed, the laser beam is irradiated to the contact portion between the pedestal 11 and the lens holder 12 and the contact portion between the pedestal 11 and the housing 10. Each member is laser welded to each other.
As the order of laser welding, the base and the casing are welded first, and then the base and the lens holder are welded.
[0019]
In addition, since the lens holder is in contact with the inclined surface of the pedestal, it is possible to ensure a wide laser irradiation angle when irradiating the laser, and the workability during welding is greatly improved.
Furthermore, as shown in FIG. 2, a wider irradiation angle can be ensured by inclining the surface including the contact portion of the lens holder 12. In addition, by making the cross-sectional shape of the pedestal 11 triangular, a wide irradiation angle can be provided even when welding the pedestal and the optical module casing.
In laser welding, spot welding is desirable from the viewpoint of reducing the displacement of each member and the generation of mechanical stress, but it is also possible to continuously weld linearly in order to increase the holding strength of the lens.
[0020]
Then, after the laser welding is completed, the arm 15 of the positioning device is removed from the lens holder 12, and the assembly of the lens fixing device is completed.
In the above, laser welding is used as a joining method of each member. However, the present invention is not limited to this, and a joining method of each component known in the technical field such as an adhesive is used. Is possible.
[0021]
Next, a second embodiment of the lens fixing device according to the present invention will be described.
FIG. 3 shows a state (a) before installation of the pedestal in the lens fixing device and a state (b) after installation of the pedestal.
As shown in FIG. 3, when the lens holder 22 holding the lens 23 is disposed in a narrow space of the optical module housing 20, a small pedestal is provided below the lens holder so that the optical axis of the lens is aligned. It is possible to sandwich the lens holder from a vertical direction. However, when such a pedestal is arranged and there is no space for position adjustment, as shown in FIG. The two pedestals 21 are bridged on the side wall (in FIG. 3B, the side wall is formed in a stepped shape but is not limited to this), and the lens holder 22 is suspended from the pedestal 21. It is also possible to fix. Thus, when the pedestal is fixed at a position close to the upper surface of the housing, the workability of laser welding is greatly improved.
[0022]
In the method for assembling the lens fixing device as shown in FIG. 3, first, the lens holder 22 is arranged at a predetermined position by the arm 25 of the positioning device, as in the case of FIG. Next, the pedestal 21 is brought into contact with the lens holder 22 so as to sandwich the lens holder from the optical axis direction of the lens, and the lens holder 22, the pedestal 21, and the optical module housing 20 are laser-welded.
In addition, an inclined surface is formed on the pedestal 21 in order to facilitate the laser welding operation and to make the pedestal properly come into contact with one side of the lens holder.
[0023]
Furthermore, a third embodiment of the lens fixing device according to the present invention will be described.
FIG. 4 is a cross-sectional view of the lens fixing device perpendicular to the optical axis.
Reference numeral 30 denotes an optical module housing, 33 a lens, 32 a lens holder for holding the lens, and 31 a pedestal for supporting the lens holder.
The feature of this embodiment is that the inner surface of the optical module housing 30 on which the base 31 is installed has an inclined surface 36 that decreases toward the center.
The inclined surface 36 allows the pedestal 31 to move by its own weight toward the lens holder 32. For this reason, the pedestal can always be kept in close contact with the lens holder. The operation of pressing the lens toward the lens holder can be omitted.
[0024]
【The invention's effect】
As described above, according to the lens fixing device and the manufacturing method thereof according to the present invention, the number of parts when fixing the lens to a predetermined position of the optical module housing is small, and the size can be reduced. In addition, it is possible to realize a lens fixing device with good workability during assembly and a manufacturing method thereof.
[Brief description of the drawings]
FIG. 1 is a diagram showing a cross section of a conventional lens fixing device. FIG. 2 is a diagram showing a first embodiment of a lens fixing device according to the invention. FIG. 3 is a second embodiment of a lens fixing device according to the invention. It is a figure which shows an example, (a) shows before pedestal installation, (b) shows after pedestal installation.
FIG. 4 is a diagram showing a third embodiment of the lens fixing device according to the present invention.
13, 23, 33 Lens 12, 22, 32 Lens holder 10, 20, 30 Housing 11, 21, 31 Base

Claims (5)

In a lens fixing device for fixing a lens at a predetermined position inside a housing for an optical module,
A lens holder for holding the lens;
Having at least two pedestals having inclined surfaces in contact with the lens holder;
Pedestal and the housing, and the pedestal and both the and the lens holder are joined,
Two planes including the abutting portions that abut each pedestal in the lens holder are inclined surfaces that are inclined in the opposite direction to the inclined surface of each pedestal that abuts, and the inclined surface of the lens holder and the inclined surface of the pedestal cooperatively the irradiation angle of the laser widely ensured in accordance with the laser welding of the abutting portion, the lens fixing apparatus characterized by direct irradiation shines a laser from該筺body outside the abutment portion.   2. The lens fixing device according to claim 1, wherein the pedestal is arranged so as to sandwich the lens holder from a direction perpendicular to the optical axis of the lens.   The lens fixing device according to claim 1, wherein the pedestal is disposed so as to sandwich the lens holder horizontally and perpendicularly to the optical axis of the lens.   4. The lens fixing device according to claim 1, wherein the pedestal has a cross-sectional shape of a triangle having the inclined surface on one side. 5. In the manufacturing method of the lens fixing device for fixing the lens at a predetermined position inside the housing for the optical module,
A lens holder for holding the lens;
Having at least two pedestals having inclined surfaces in contact with the lens holder;
Two planes including the abutting portion that abuts each pedestal in the lens holder are inclined surfaces inclined in the opposite direction to the inclined surface of each abutting pedestal,
While holding the lens holder by a positioning device, positioning at the predetermined position,
Next, the inclined surface of the pedestal is brought into contact with the lens holder, and the inclined surface of the lens holder and the inclined surface of the pedestal cooperate to ensure a wide laser irradiation angle for laser welding, Laser welding the pedestal and the lens holder by directly irradiating the corresponding contact portion with laser from outside the housing, and joining the pedestal and the housing,
Thereafter, the holding of the lens holder by the positioning device is released.

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