JPH0886945A - Welding structure of optical device - Google Patents

Abstract

PURPOSE: To make it possible to decide whether the weld zone between a first pipe and a second pipe is good or not by visual observation, etc., directly from outside with an optical device including a structure in which the first pipe housing optical parts and the second pipe to be fitted to the first pipe are fixed by laser welding. CONSTITUTION: The second pipe 2 has an aperture 5 in the part of the side face to be irradiated with a laser beam and more particularly this aperture 5 consists of a shape including a width small than the beam diameter of the laser beam and a width larger than the beam diameter. The pipe is surely welded and fixed in the part where the width is smaller than the beam diameter. In addition, the outer peripheral part of the first pipe 1 and the side face of the aperture of the second pipe 2 are visible from the part of the width larger than the beam diameter and, therefore, the direct inspection of the welding state of both pipes is possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding structure for an optical device, and more particularly to a fixing structure for laser-welding a component for housing an optical component such as a lens in the optical device and another component for fixing the component.

[0002]

2. Description of the Related Art FIG. 3 is a perspective view showing an internal structure of an optical semiconductor module, in which (a) shows a state before an optical fiber terminal is fixed and (b) shows a state after fixing. There is. A semiconductor laser chip (not shown) is housed in the semiconductor laser package 6, and the light emitted from the semiconductor laser chip is collected by an aspherical lens 8 arranged in front of the semiconductor laser package 6 to produce an optical fiber terminal. It is coupled to an optical fiber (not shown) housed in 12.

Next, the fixing structure of optical components such as lenses in such an optical device is shown in FIGS. 3 (a) and 3 (b).
Will be described separately for each step.

First, as shown in FIG. 4 (a), the lens holder 9 accommodating the aspherical lens 8 is fitted into the flanged pipe 10, and the flanged pipe 10 is further fitted.
Is a semiconductor laser package 6 having a metal cap 7.
Is placed in front of the cap. Then, the light emitted from the semiconductor laser chip is emitted from the semiconductor laser package 6
The position is adjusted in the XY directions so as to be straight without tilting with respect to the central axis of the. The lens holder 9 is adjusted in position in the flanged pipe 10 so that the main plane of the aspherical lens 8 and the semiconductor laser chip have a desired distance. After the position adjustment is completed, the side surface of the flanged pipe 10 is externally irradiated with, for example, a YAG laser to locally melt the irradiation portion on the side surface of the flanged pipe 10, and the side surface of the lens holder 9 is flanged by so-called penetration welding. With pipe 1
It sticks to the inner wall of 0. Further, the joint between the cap 7 and the flanged pipe 10 is irradiated with laser and is fixed by so-called fillet welding. The lens holder 9 is an integrated lens and a metal ring that houses the lens, and is generally integrated when the aspherical lens 8 is manufactured by glass molding.

After that, as shown in FIG. 3B, the position of the optical fiber terminal 12 is adjusted via a support on the end surface of the flanged pipe 10 opposite to the side where the package 6 is joined. It is fixed. Here again, the flanged pipe 10 and the support 11 are irradiated with a laser at the joint to fillet the weld, and the support 11 and the optical fiber terminal 1 are also welded.
The laser beam 2 is externally irradiated to the side surface of the support 10 and is fixed by penetration welding.

[0006]

For fixing components used in an optical device, welding fixing by laser irradiation is widely used because it is easy to manufacture and highly reliable. As mentioned above, the weld fixing of these parts is
Due to the difference in structure, it is roughly divided into a method called penetration welding that irradiates the surface of one component with laser to fix both parts, and a fillet welding that irradiates the joint of both parts with laser to fix them. It

In fillet welding, even if the laser irradiation power is insufficient or the focus is deviated by any chance, the portion irradiated with the laser and melted can be observed from the outside. It is easy to confirm.

On the other hand, in the penetration welding, as can be seen from the schematic view of the welding structure shown in FIG. 4 and the sectional view thereof shown in FIG. 5, observation of the surface portion of the second pipe 2 irradiated with the laser is performed. However, the molten state of the first pipe 1 inside cannot be observed from the outside. Therefore, there is a problem that even if a welding failure occurs due to the above-mentioned reason, it cannot be easily inspected.

In the penetration welding, in general, the laser-irradiated component is surely melted, and the member thereunder is also melted. Therefore, the thickness of the former component is thin. For example, when another component is fixed to a component made of metal by YAG laser irradiation, the laser output is 8 J and the thickness is about 0.3 mm. However, when a pipe is processed, a dimensional error is caused to some extent. Therefore, through-welding may cause insufficient welding even when it is thicker than a desired wall thickness.

[0010]

A welded structure for an optical device according to the present invention comprises a first pipe and a second pipe fitted to the first pipe.
In the welding structure of the optical device for irradiating a laser beam from the outside of the side surface of the second pipe and fixing the same by welding, the second pipe has an opening portion on the side surface where the laser beam is irradiated. It is characterized by being. In particular,
The aperture is characterized in that it has a shape including a width smaller and a width larger than the beam diameter of the laser beam. Specifically, it is a slotted opening having a width smaller than the beam diameter and a large length.

[0011]

[Function] While being securely welded and fixed in a portion whose width is smaller than the beam diameter,
Since the outer peripheral portion of the first pipe and the side surface of the opening portion of the second pipe can be seen, the welded state of both pipes can be directly observed.

[0012]

The present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the welding structure of the device of the present invention. In addition, FIG. 2 shows AA of FIG.
It is sectional drawing in a line. Here, a welding structure used for mounting the lens of the optical semiconductor module described in the related art will be described as an example.

The first pipe 1 containing the lens 3 is
It is inserted into the second pipe 2 and positioned at a position suitable for coupling. The slot-shaped opening portion 5 provided on the side surface of the second pipe 2 has a sufficient length so as to overlap with the side surface portion of the first pipe 1 even when the first pipe 1 is arbitrarily positioned. And has a sufficiently narrow width as compared with the width of the fusion zone 4 generated during welding. When the first pipe 1 is welded and fixed to the second pipe 2, the slot 5
When the welding position is determined so that the fusion portion 4 and the fusion portion 4 overlap with each other, the fusion state of the side surface of the first pipe 1 can be visually confirmed.

The opening 5 of the second pipe 2, which is a feature of the above-described welded structure of the optical device of the present invention, will be specifically described by taking an example of the optical semiconductor module described in the prior art. When the power of the irradiated laser is 8 J and the beam diameter is about 0.5 mm, the diameter of the fusion zone (nugget) is about 0.7 mm. So, in one embodiment,
The slits are processed to have a width of 0.3 mm and a length of 1.5 mm. By making the width slightly smaller than the nugget diameter, it is possible to securely weld and fix, and the longitudinal direction is larger than the nugget diameter.
The joint between the inner wall surface of the pipe 2 and the surface of the first pipe 1 can be observed. This processing may be performed by a blade saw, but precision die casting is more suitable for mass production.

In the first embodiment, stainless steel suitable for welding is used for the first pipe 1 and the second pipe 2, but Kovar or another material may be used as long as it is a metal capable of welding. Although the lens is used as the optical component in this example, it goes without saying that the optical fiber terminal and the support described in the prior art can be fixed to the support. Further, it may be applied to a component holding an optical crystal or the like instead of the lens.

[0017]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, in a welded structure of a pipe in which an optical component is housed and an optical device fitted to the pipe and fixed by welding with a laser from the outside, a laser-irradiated outer side. The welded state can be easily confirmed visually by providing the pipe with an opening having a width that is partly larger than the diameter of the nugget formed by welding. This can prevent the need for welding and improve the reliability of the fixed portion of the optical device.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a welding structure of an optical device of the present invention.

FIG. 2 is a cross-sectional view of FIG. 1 taken along the line AA.

FIG. 3 is a perspective view of an optical semiconductor module.

FIG. 4 is a perspective view of a welding structure of a conventional optical device.

5 is a cross-sectional view of FIG. 3 taken along the line AA.

[Explanation of symbols]

 1 1st pipe 2 2nd pipe 3 Lens 4 Welding part (nugget) 5 Opening part 5a Part of width larger than beam diameter in opening part 5b Part of width smaller than beam diameter in opening part 6 Laser Package 7 Cap 8 Aspherical lens 9 Lens holder 10 Pipe with flange 11 Support 12 Optical fiber terminal

Claims (6)

[Claims] 1. A laser beam is radiated from the outside to the side surface of a second pipe that fits around the outer periphery of the first pipe in which the optical component is accommodated, and the first pipe is welded and fixed to the second pipe. In the welding structure of the optical device, the second pipe has an opening portion in a portion of the side surface that is irradiated with the laser beam. 2. The welded structure for an optical device according to claim 1, wherein the hole has a shape including a width smaller and a width larger than a beam diameter of the laser beam. 3. The optical device according to claim 2, wherein the aperture has a slotted shape having a width smaller than the beam diameter and a length larger than the beam diameter. Welded structure. 4. The welded structure for an optical device according to claim 2, wherein the first pipe and the second pipe are made of metal. 5. The welded structure for an optical device according to claim 4, wherein the first pipe holds an optical component. 6. The welded structure for an optical device according to claim 6, wherein the optical component is a lens.