JP4079730B2 - Semiconductor laser fixing apparatus and semiconductor laser fixing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor laser fixing device and a semiconductor laser fixing method, and more particularly to a semiconductor laser fixing device and a semiconductor laser fixing method for fixing a can type semiconductor laser used as a light source of an optical pickup.
[0002]
[Prior art]
An optical pickup that records a signal on an optical disk and reproduces a recorded signal uses a can-type laser diode (hereinafter referred to as “semiconductor laser”) as a light source.
[0003]
A semiconductor laser is composed of a cylindrical stem that serves as a pedestal for mounting a chip that emits laser light, a cap placed on the stem, and a lead provided on the opposite surface of the stem cap. It is fixed to a semiconductor laser fixing device (hereinafter referred to as “holder”).
[0004]
As a method of fixing the semiconductor laser to the mounting hole formed in the holder, there are a method of fixing by caulking and a method of fixing by press-fitting.
[0005]
First, a method for fixing the semiconductor laser 6 by caulking will be described with reference to FIG. After the semiconductor laser 6 is inserted into the mounting hole 4 of the holder 2 from the cap side, the surface of the holder 2 is driven at three locations at equal intervals using a sharp hard jig. By this driving, a hole 8a is formed on the surface of the holder, and as a result, the inner surface of the mounting hole 4 is deformed to form an expanded portion 8b. The semiconductor laser 6 is sandwiched from three directions by the expanding portion and fixed to the holder 2.
[0006]
At this time, the diameter of the mounting hole 4 is set a little larger than the largest case in consideration of the variation in the outer diameter of the stem of the semiconductor laser 6 to be used, and the expansion portion 8b according to the outer diameter of the stem. The semiconductor laser 6 is fixed by adjusting the method of swelling. For this reason, since it is not necessary to prepare the holder 2 of a different shape according to the outer diameter of the stem, it is excellent in mass productivity.
[0007]
Next, a method for fixing the semiconductor laser to the holder by press fitting will be described. In order to prevent damage to the semiconductor laser, the diameter of the mounting hole of the holder is slightly smaller than the outer diameter of the stem of the semiconductor laser (for example, about 10 μm), and the laser diode is placed on the cap side in the mounting hole. Push in. Since the holder and the stem are made of aluminum alloy and brass, respectively, they are elastically deformed and are in close contact with each other. For this reason, the heat generated by the semiconductor laser is transmitted to the housing of the optical pickup through the holder made of an aluminum alloy having good thermal conductivity, so that the heat dissipation is excellent.
[0008]
[Problems to be solved by the invention]
However, in the fixing method by caulking, the heat generated by the semiconductor laser is transmitted from the stem to the holder through the tip of the expansion portion formed on the inner surface of the mounting hole of the holder. For example, when the semiconductor laser is crimped at three locations, there are only three expansion portions, and the heat transfer area between each expansion portion and the stem is small, so that the heat generated by the semiconductor laser cannot be sufficiently transmitted to the holder.
[0009]
For this reason, the generated heat is stored in the semiconductor laser and raises the temperature of the semiconductor laser. Due to this temperature rise, the luminous efficiency of the semiconductor laser is reduced, and even if the applied current is increased, the predetermined maximum light intensity cannot be obtained, so that proper recording on the optical disc cannot be performed and the life of the semiconductor laser is shortened. is there.
[0010]
Further, in the fixing method by press-fitting, in order to prevent the semiconductor laser from being broken, the diameter of the mounting hole of the holder is set to the stem in order to push the semiconductor laser into the holder within a range where both the stem and the holder of the semiconductor laser are elastically deformed. It is preferable that it is slightly smaller than the outer diameter (about 10 μm).
[0011]
However, in semiconductor lasers used for mass production, the difference in the outer diameter of the stem between the largest value and the smallest value is 30 μm with respect to the standard value of 5.6 mm. For this reason, in order to prevent the can-type laser diode from being broken by press-fitting and to bring it into close contact with the holder, several types of holders having different mounting hole diameters must be prepared in accordance with the outer diameter of the semiconductor laser stem. It is not suitable for mass production.
[0012]
Therefore, the main object of the present invention is to improve the heat dissipation property for releasing the heat generated from the semiconductor laser to the holder which is the semiconductor laser fixing device, and at the same time, even if the accuracy of the outer diameter of the semiconductor laser is not good, It is to provide a holder that is a semiconductor laser fixing device that does not need to be prepared according to the outer diameter of the laser.
[0013]
[Means for Solving the Problems]
The first invention is a semiconductor laser fixing device mounting hole is formed for fixing the semiconductor laser, wherein a portion of the side surface to form at least one injection hole intersects the portion of the side surface of the mounting hole This is a semiconductor laser fixing device.
[0014]
A second invention is a semiconductor laser fixing method for fixing a semiconductor laser to an attachment hole formed in a semiconductor laser fixing device, wherein the semiconductor laser is inserted into the attachment hole, and an expansion portion formed on the inner surface of the attachment hole, The step of fixing by sandwiching the semiconductor laser, and the solidification by injecting an adhesive into the injection hole formed in the semiconductor laser fixing device, part of the side surface intersecting with part of the side surface of the mounting hole, A semiconductor laser fixing method including a step of bonding a semiconductor laser and a mounting hole.
[0015]
[Action]
A semiconductor laser is inserted and fixed in a mounting hole of a holder, which is a semiconductor laser fixing device, and a part of its side surface is thermally conductive from an injection hole formed so as to intersect a part of the side surface of this mounting hole. A good adhesive is injected to bond the semiconductor laser fixing device and the semiconductor laser over a wide area. In this case, since it is not necessary to prepare a plurality of types of semiconductor laser fixing devices at the time of mass production of the optical pickup, it is possible to improve mass productivity and at the same time, the semiconductor laser and the semiconductor laser fixing device are bonded in a wide area, so that the semiconductor The heat dissipation of the heat generated by the laser is improved.
[0016]
Moreover, it is preferable that the injection hole penetrates from one surface different from the surface on which the mounting hole of the semiconductor laser fixing device is formed to another surface facing the injection hole. In this case, by checking that the adhesive injected into the injection hole from the opening on one surface has advanced through the injection hole and reached the opening on the other surface, the injected adhesive becomes a semiconductor. It can be indirectly confirmed that the space between the laser and the inner surface of the mounting hole has spread.
[0017]
Moreover, it is preferable that the injection hole is formed in a line symmetrical position with respect to the mounting hole. In this case, the stress generated when the adhesive injected into the injection hole is solidified is also axisymmetric, and the optical system of the optical pickup can be prevented from deteriorating with time.
[0018]
The semiconductor laser fixing method for fixing the semiconductor laser to the mounting hole formed in the semiconductor laser fixing device is as follows. First, the semiconductor laser is inserted into the mounting hole, and an expansion portion is formed on the inner surface of the mounting hole. The holder is a semiconductor laser fixing device, and a part of the side surface of the holder intersects with a part of the side surface of the mounting hole, and is different from the surface on which the mounting hole of the semiconductor laser fixing device is formed. An injection hole is formed so as to penetrate from one surface to the opposite surface, and an adhesive is injected into the space between the semiconductor laser and the mounting hole from the injection hole to solidify, so that the semiconductor laser and the mounting hole are formed. Bonding. In this case, since it is not necessary to prepare a plurality of types of semiconductor laser fixing devices at the time of mass production of the optical pickup, it is possible to improve mass productivity and at the same time, the semiconductor laser and the semiconductor laser fixing device are bonded in a wide area, so that the semiconductor The heat dissipation of the heat generated by the laser is improved.
[0019]
In one embodiment of the present invention, the adhesive to be injected from the injection hole is any one of a silicon adhesive or silver paste containing alumina particles having good thermal conductivity.
[0020]
【The invention's effect】
According to the present invention, since it is not necessary to prepare a plurality of types of semiconductor laser fixing devices at the time of mass production of the optical pickup, it is possible to improve mass productivity and at the same time, the semiconductor laser and the semiconductor laser fixing device are thermally conductive. Since it is bonded with a good adhesive, the heat transfer area is expanded and the heat dissipation of the heat generated by the semiconductor laser is improved.
[0021]
The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.
[0022]
【Example】
With reference to FIG. 1, the Example of the holder 10 which fixes the semiconductor laser 16 used as a light source of an optical pick-up is demonstrated.
[0023]
Here, the semiconductor laser 16 includes a cylindrical stem 16a, a cap 16b fixed on the stem 16a, and a plurality of leads extending from the stem 16a in the opposite direction to the cap 16b, and emits laser light. The chip is fixed to the stem 16a and covered with a cap 16b. The material of the stem 16a is brass, and the material of the cap 16b is stainless steel.
[0024]
The holder 10 is for fixing the semiconductor laser 16 and is easily elastically deformed and needs to have good heat dissipation. Therefore, the material is most preferably an aluminum alloy, but when heat dissipation is more important. May be a copper alloy. A mounting hole 12 is provided near the center of the holder 10 so that the semiconductor laser 16 can be inserted.
[0025]
The diameter of the mounting hole 12 is about 50 μm larger than the largest case in consideration of the variation in the outer diameter of the stem 16a of the semiconductor laser 16 to be used. The expansion method of the expansion part is adjusted according to the outer diameter of 16a. For this reason, it is not necessary to prepare the holder 10 having a different shape according to the outer diameter of the stem 16a. Further, the holder 10 has an injection hole penetrating from the upper surface to the lower surface of the holder 10 so as to intersect the mounting hole 12. 14 are formed in parallel at two symmetrical positions across the mounting hole.
[0026]
The intersection of the mounting hole 12 and the injection hole 14 will be described with reference to FIG. 2A is a cross-sectional view when the holder 10 of FIG. 1 is cut along the XZ plane, and FIG. 2B is a cross-sectional view when the holder 10 is cut along the XY plane. As can be seen from these drawings, in the mounting hole 12, the diameter of the portion where the stem 16a of the semiconductor laser 16 is stored is smaller than the diameter of the portion where the cap 16b is stored.
[0027]
A part of each of the left and right injection holes 14 of the mounting hole 12 is formed so as to bite into a portion where the stem 16a is accommodated and larger than a portion where the cap 16b is accommodated. Therefore, the two injection holes 14 are connected to the left and right sides of the mounting hole 12 where the stem 16a is accommodated.
[0028]
The diameter of the mounting hole 12 is, for example, about 30 μm larger than the design value so that it can be inserted even when the outer diameter of the stem 16a of the semiconductor laser 16 deviates most from the design value 5.6 mm. ing. At this time, the diameter of the injection hole 14 is preferably about 1 mm to about 2 mm.
[0029]
A method for fixing the semiconductor laser 16 using the holder 10 will be described. First, as described in the prior art section, the semiconductor laser 16 is inserted into the mounting hole 12 of the holder from the cap side, and the stem 16a of the semiconductor laser 16 is crimped to the holder 10 and fixed.
[0030]
Next, an adhesive having good thermal conductivity is injected from the openings of the two injection holes 14 provided in the holder 10. The injected adhesive proceeds while discharging the air in the injection hole 14 from the opening on the opposite side of the injection hole 14. When this adhesive reaches a position where the injection hole 14 intersects the mounting hole 12, it spreads into the space between the stem 16a of the semiconductor laser 16 and the inner surface of the mounting hole 12 of the holder 10 and solidifies.
[0031]
For this reason, since the semiconductor laser 16 and the holder 10 are bonded with a large surface area, the heat transfer area where heat generated by the semiconductor laser 16 is transmitted to the holder 10 is expanded, and heat dissipation is improved. Furthermore, a part of the adhesive proceeds through the injection hole 14 and stops reaching the opening on the opposite side due to the surface tension of the adhesive. Thus, if it can be confirmed that the adhesive has reached the opening on the opposite side, it can be considered that the adhesive has also spread to the space between the inner surface of the mounting hole 12 and the stem 16a.
[0032]
The adhesive to be used needs to have good thermal conductivity, and for example, a silicon adhesive or silver paste containing alumina particles is preferable.
[0033]
In the embodiment of FIG. 1, the injection hole 14 penetrates from the upper surface to the lower surface of the holder 10. However, the injection hole 14 does not necessarily have to penetrate, and may extend from the upper surface or the lower surface of the holder 10 to a position at least intersecting with the attachment hole 12, for example. In this case, the adhesive injected from the injection hole 14 proceeds to the position where the injection hole 14 and the mounting hole 12 intersect while discharging the air in the injection hole 14 through the mounting hole 12, and between the stem 16 a and the holder 10. It spreads and solidifies.
[0034]
Therefore, in this case as well, since the semiconductor laser 16 and the holder 10 are bonded to each other by a large area by the adhesive, the heat transfer area in which the heat generated by the semiconductor laser is transmitted to the holder is expanded as in the case where the injection hole penetrates. , Heat dissipation is improved. However, in this case, it cannot be easily confirmed that the adhesive spreads in the space between the stem and the holder.
[0035]
In the embodiment of FIG. 1, the two injection holes 14 are formed at positions that are symmetrical with respect to the mounting hole 12. This is because each component is preferably configured to be laterally or vertically symmetric in consideration of temporal stability and thermal stability of the optical system of the optical pickup. For this reason, the injection hole 14 is also provided on the left and right sides with respect to the mounting hole 12 of the holder 10 so that the stress generated when the adhesive injected into the injection hole 14 is solidified is also symmetrical.
[0036]
However, the injection holes 14 are not necessarily provided symmetrically. That is, the number of injection holes 12 may be different on the left and right of the mounting hole 12, and the provided position may be shifted from the symmetrical position even if the number is the same. However, if too many injection holes 14 are provided, the strength of the holder 10 is weakened. Therefore, it is preferable that two injection holes are provided, and they are provided symmetrically with respect to the mounting hole 12.
[0037]
In the embodiment of FIG. 1, the injection hole 14 is formed from the upper surface to the lower surface of the holder 10. The injection hole 14 only needs to intersect with the attachment hole 12 inside the holder 10. For example, the injection hole 14 may be formed from the right side surface to the left side surface of the holder 10, or is formed in a direction crossing the holder 10 obliquely. May be.
[0038]
However, considering the ease of forming the injection hole 14 and the ease of passing through the adhesive injection hole 14, the injection hole 14 is formed vertically from the upper surface to the lower surface of the holder 10 as in the embodiment of FIG. It is preferable to form.
[0039]
The most preferred embodiment of the semiconductor laser fixing device of the present invention is the case shown in FIG. 1, but is a modification of the injection hole 14 as described above, or a case where the injection hole 14 is a combination of two or more thereof. This also has the same effect as the semiconductor laser fixing device of the present invention.
[Brief description of the drawings]
FIG. 1 is an illustrative view showing one embodiment of the present invention;
FIG. 2 is an illustrative view showing a cross section of the embodiment in FIG. 1;
FIG. 3 is an illustrative view showing a conventional example.
[Explanation of symbols]
10 ... Holder (semiconductor laser fixing device)
12 ... Mounting hole 14 ... Injection hole 16 ... Semiconductor laser

Claims (4)

In the semiconductor laser fixing device in which the mounting hole for fixing the semiconductor laser is formed, a part of the side surface thereof intersects with a part of the side surface of the mounting hole, and the surface of the semiconductor laser fixing device in which the mounting hole is formed; A semiconductor laser fixing device, wherein at least one injection hole penetrating from one different surface to another opposing surface is formed. Said injection hole, the formed the mounting holes at positions axisymmetric, the semiconductor laser fixing apparatus according to claim 1. A semiconductor laser fixing method for fixing a semiconductor laser to an attachment hole formed in a semiconductor laser fixing device,
Inserting the semiconductor laser into the mounting hole, and fixing the semiconductor laser by sandwiching it with an expanding portion formed on the inner surface of the mounting hole;
Formed on the semiconductor laser fixing device, part of the side surface thereof intersects with part of the side surface of the mounting hole, and faces from one surface different from the surface on which the mounting hole of the semiconductor laser fixing device is formed. A method of fixing a semiconductor laser, comprising a step of bonding the semiconductor laser and the mounting hole by injecting and solidifying an adhesive having good thermal conductivity into an injection hole penetrating another surface . 4. The semiconductor laser fixing method according to claim 3 , wherein the adhesive is any one of a silicon adhesive containing silver particles and a silver paste.

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