JP3553281B2 - Lens parts - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an airtight lens component used for an optical semiconductor package.
[0002]
[Prior art]
Conventionally, optical semiconductor modules contain only a light-emitting element or a light-receiving element in a cylindrical container. In recent years, especially in optical semiconductor modules for optical communication, high-quality light beams are required. In many cases, the form of the box type can take in a control function or the like. FIG. 3 is a sectional view of an example of the optical semiconductor module. This optical semiconductor module includes a semiconductor laser 10 and a collimator lens 6 as optical semiconductors in an optical semiconductor package 4 (hereinafter referred to as package 4). The semiconductor laser 10 is fixed to the spacer 13 via the subcarrier 11 and the base 12, and the spacer 13 is fixed to the bottom 4 d of the package 4. The base 12 is provided with a collimator lens 6 as a lens system. The collimator lens 6 is fixed to a lens holder 6a, and the position and angle of the lens holder 6a are adjusted so that the light emitted from the semiconductor laser 10 becomes a parallel beam. Fixed.
[0003]
The light beam emitted from the collimator lens 6 is guided to the outside through the hole 4a on the side surface of the package 4. This light beam is condensed by the lens 2 inserted into the metal sleeve 7 and is incident on the optical fiber 9 fixed to the ferrule 8. The ferrule 8 is inserted into the sleeve 7 and fixed using YAG welding or the like.
[0004]
The sleeve 7 includes the lens 2 fixed to the through hole 7a with an adhesive 3. The sleeve 7 is fitted in the hole 4 a of the metal package 4 having good wettability with respect to solder, and the outer surface thereof is hermetically fixed using the solder 5.
[0005]
[Problems to be solved by the invention]
However, in the mounting position of the sleeve 7, many accumulative factors such as the eccentricity between the outer periphery thereof and the through hole 7 a, the mounting accuracy of the lens 2, the processing accuracy of the hole 4 a of the package 4, and the mounting accuracy of the sleeve 7 are accumulated. If a position shift element exists and any one of the elements deviates from a predetermined accuracy, the optical axis of the optical system after the lens 2 deviates from the optical axis 20 of the light beam emitted from the semiconductor laser 10 to the optical semiconductor module. There is a problem that the output is out of the standard, resulting in a defective product. On the other hand, if the processing accuracy and mounting accuracy of each part are strict, there is a problem that the cost increases.
[0006]
In addition, after the semiconductor laser 10 or the like is assembled in the package 4, if the airtight structure cannot be formed by the lid 4 f, the assembly process of the optical semiconductor module should be performed consistently until the last optical fiber 9 is assembled. Alternatively, a transparent window member 4e must be provided on the inner opening surface of the hole 4a of the package 4, and there is a problem in the degree of freedom of the manufacturing process.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems in the production of the conventional optical semiconductor module and to provide a lens component that enables efficient production of the optical semiconductor module.
[0008]
[Means for Solving the Problems]
The lens component according to the present invention has a through hole at the top, a cylindrical hollow portion extending from the top and having a uniform outer diameter, and a flange at the open end of the cylindrical hollow portion. A lens cap fitted and fixed in a hole of an optical semiconductor package including a metal cap having a metal cap and a lens hermetically sealed in a through hole at the top of the metal cap. The outer diameter of the portion is determined to be a value provided with a gap for adjusting the joining position with respect to the inner diameter of the hole of the optical semiconductor package into which the optical semiconductor package is inserted, and the optical semiconductor package is provided on the surface of the flange portion of the metal cap. A small projection ring for hermetic welding for fixing to the opening end face of the hole.
[0009]
According to the lens component of the present invention, the outer diameter of the cylindrical hollow portion of the metal cap is determined to be a value provided with a gap for adjusting the joining position with respect to the inner diameter of the hole of the optical semiconductor package to be fitted. In addition, since a small projection ring for airtight welding for fixing to the opening end surface of the hole of the optical semiconductor package is formed on the surface of the flange portion of the metal cap, the cylindrical shape of the metal cap of the lens component is formed. After the hollow part is fitted into the hole of the optical semiconductor package and the lens component is adjusted to a position within a predetermined range in a direction orthogonal to the optical axis of the optical semiconductor, the minute projection ring formed on the surface of the flange is removed. The minute protrusion ring can be melted and hermetically fixed to a predetermined mounting position only by bringing the optical semiconductor package into contact with the opening end surface of the hole of the optical semiconductor package and flowing a predetermined current between the optical semiconductor package and the lens component.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The lens component of the present invention has a through hole at the top of the metal cap, the lens is hermetically fixed to the through hole, and a cylindrical hollow having a uniform outer diameter extending from the top. The uniform outer diameter is smaller than the inner diameter of the hole of the optical semiconductor package (hereinafter, referred to as a package again), and the gap with the inner diameter of the hole can be used for adjusting the joining position. On the surface of the flange provided at the opening end of the cylindrical hollow portion, a minute projection ring for airtight welding for fixing to the opening end surface of the hole of the package is formed, and fitted into the hole of the package. After the position of the optical semiconductor housed in the package in the direction orthogonal to the optical axis is adjusted, the minute projection ring is brought into contact with the opening end face of the hole of the package and is energized to be hermetically fixed at a predetermined mounting position. Things.
[0011]
As the metal cap, a material such as stainless steel can be used as long as it is a metal material that can be welded by energization.In particular, the expansion coefficient is close to that of the optical glass material used for the lens. Materials such as iron-nickel alloys and iron-nickel-cobalt alloys (so-called Kovar alloys) that can be mass-produced at low cost are preferable. As the through-hole at the top of the metal cap, one having a slightly larger diameter than the lens to be hermetically fixed, one having a slightly smaller diameter than the lens, one having a diameter substantially the same as the inner diameter of the cylindrical hollow portion, etc. is there. The length of the cylindrical hollow portion extending from the top of the metal cap and having a uniform outer diameter is determined according to the focal length of the lens, the mounting form of the lens component to the package, and the like. The value is determined by providing a gap for adjusting the bonding position with respect to the inner diameter of the hole of the optical semiconductor package to be inserted. The flange at the open end of the cylindrical hollow portion has a diameter larger than that of the hole of the package, and the surface on the package side has a cut at the time of welding to be fixed to the open end of the hole of the package. A small projection ring for airtight welding that does not cause air leakage is formed, and its cross-sectional shape is a triangular shape or a wedge shape with a point that touches the opening end surface, and current concentrates at the tip by energization. It is preferable that the contact portion be easily melted.
[0012]
As the lens, a spherical lens obtained by processing optical glass such as BK-7 or TaF-3 into a spherical shape, or a drum-shaped lens obtained by grinding a spherical lens and processing a joint with a metal cap into a cylindrical shape can be used. The lens is heat-treated in a through hole of a metal cap using an adhesive made of low-melting glass or the like, and is air-tightly fixed. An antireflection film, a filter, or the like may be provided on the surface of the lens according to the purpose.
[0013]
When the optical semiconductor package is made of metal suitable for welding, it is sufficient to provide a hole and a smooth opening end face at a predetermined position, but otherwise, the hole of the optical semiconductor package is not required. A metal ring-shaped member suitable for welding is attached to the opening end face by insert injection molding or brazing, etc., and when the minute projection ring of the lens part abutting the ring surface is energized and melted, Parts should be airtight.
[0014]
【Example】
1 and 2 are explanatory views of a lens component according to the present invention, in which 1 indicates a metal cap, and the same parts as those in FIG. I have.
[0015]
In the lens component of the present invention, as shown in FIG. 1, a through hole 1b having a diameter of 1.6 mm is formed in the center of a top 1a of a metal cap 1 made of Kovar alloy, and extends from the top 1a. There is a cylindrical hollow portion 1c having a uniform outer diameter of 4.0 mm having a length of 4.0 mm corresponding to the fixed position of the lens 2 in the optical axis direction, and is provided at an open end 1d of the cylindrical hollow portion 1c. It has a flange 1e having a diameter of 8 mm and a thickness of 1.0 mm. A small projection ring 1f having a wedge-shaped cross section of 0.1 mm in height for hermetic welding is formed on the surface of the flange 1e on the side in contact with the opening end surface of the hole of the package. A 1.5 mm diameter spherical lens 2 made of optical glass material BK-7 is hermetically fixed to a through hole 1b of the top 1a of the metal cap 1 with an adhesive 3 mainly composed of low melting point glass. I have.
[0016]
A case where the above-mentioned lens component is hermetically welded and fixed to the package 4 to assemble the optical semiconductor module will be described. As shown in FIG. 2, the outer diameter of the cylindrical hollow portion 1c of the metal cap 1 of the lens component is 3.6 mm, and the outer diameter of the hole 4a of the fitted package 4 is 4.0 mm for adjusting the joining position. The gap 4c is made smaller by 0.4 mm, and the mounting position of the lens component is adjusted in the direction orthogonal to the optical axis 20 of the semiconductor laser 10 using the gap 4c. After this adjustment, the minute projections 1f for hermetic welding formed on the surface of the flange portion 1e of the metal cap 1 shown in FIG. 1 are brought into contact with the opening end surface 4b of the hole 4a of the package 4 to be energized. Melts and adheres to become 1 g of weld wheel. With this energization, the position of the lens component in the direction of the optical axis 20 falls within a predetermined standard range, and the lens component is finally welded and hermetically fixed to a predetermined mounting position. After assembling the semiconductor laser 10 and the like into the package 4 to which the lens 2 is attached and sealing it with the lid 4f to form an airtight structure, the light beam emitted from the semiconductor laser 10 is monitored using an optical power meter. The sleeve 7 provided with the ferrule 8 and the optical fiber 9 is adjusted to a position where the optical output is maximized, and fixed at that position using YAG welding or the like.
[0017]
A case where the above lens component is fixed to the package 4 will be described. First, the package 4 is accurately fixed at a predetermined position on the stage of the welding device in a direction in which the lens component can be fitted into the hole 4a, and the plus electrode of the package 4 is attached to the metal opening end surface 4b. Next, a negative electrode provided on a movable table capable of moving and adjusting the lens component in the direction of the optical axis 20 of the semiconductor laser 10 to be attached later and in a direction orthogonal to the optical axis 20 and having a central observation hole was connected. The flange portion 1e is attached to the attachment portion with the surface of the flange portion 1e on the opening end 1d side in the direction in which the lens 2 protrudes. By operating the moving table, the cylindrical hollow portion 1c of the lens component is fitted into the hole 4a, and the position in the direction orthogonal to the optical axis of the optical semiconductor is adjusted using the gap 4c for adjusting the joining position of 0.4 mm. I do. This position adjustment is performed while monitoring the center position of the lens using a simple optical fiber optical system. When the position adjustment in the direction orthogonal to the optical axis 20 is completed, the moving table is moved to the package 4 side in the direction of the optical axis 20 to bring the minute projection ring 1f of the lens component into contact with the opening end face 4b and apply forging pressure to apply the minute projection ring. 1 is pierced into the opening end face 4b of the package 4, and when a current is applied between the plus electrode and the minus electrode under predetermined conditions, air-tight welding is performed to complete the fixation, and the mounting state is as shown in FIG.
[0018]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the lens component of this invention, since the optical-semiconductor package with a lens which can be made into an airtight structure can be manufactured efficiently, the degree of freedom of the manufacturing process of an optical-semiconductor module is expanded and the component cost can be reduced. This has a practically excellent effect.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a lens component of the present invention. FIG. 2 is an explanatory view of an optical semiconductor module on which the lens component of the present invention is mounted. FIG. 3 is an explanatory view of a conventional optical semiconductor module.
DESCRIPTION OF SYMBOLS 1 Metal cap 1a Top 1b Through-hole 1c Cylindrical hollow part 1d Open end 1e Flange 1f Micro-projection ring 1g Welding ring 2 Lens 3 Adhesive 4 Package for optical semiconductor 4a Hole 4b Open end face 4c For adjusting a joining position Gap 4d Bottom 4e Window member 4f Cover 20 Optical axis

Claims (1)

A metal cap having a through hole at the top, having a cylindrical hollow portion having a uniform outer diameter extending from the top, and having a flange at the open end of the cylindrical hollow portion, A lens part fitted and fixed in a hole of an optical semiconductor package comprising a lens hermetically fixed to a through hole at the top of a metal cap,
The outer diameter of the cylindrical hollow portion of the metal cap is determined to be a value provided with a gap for adjusting the joining position with respect to the inner diameter of the hole of the optical semiconductor package to be fitted therein , and the flange of the metal cap is provided. A lens part characterized in that a minute projection ring for hermetic welding is formed on a surface of the portion for fixing to an opening end surface of a hole of an optical semiconductor package.

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