JP4547063B2 - Laser diode mount structure and mounting method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mounting structure and a mounting method thereof for laser Zada diode.
[0002]
[Prior art]
Laser diodes (hereinafter simply referred to as light emitting elements) are widely used as light sources of optical sensors for various precision length measuring devices, remote control, information recording / reproduction, and automatic machine positioning. Since the current density during operation of the light emitting element is as high as 1 to 4 kA / cm 2, heat generated by the operating current is large. If this is efficiently transmitted to the outside and not dissipated, the light emission efficiency of the light emitting element is reduced by the heat. The amount of light decreases. Therefore, in order to maintain the light amount, the operating current is further increased. From this repetition, the operating current increases and the life of the light emitting element becomes extremely short. Therefore, it is important to perform heat dissipation efficiently. Therefore, the light-emitting element is mounted on a heat dissipation block (heat sink) having high thermal conductivity, and then electrode wiring and the like are made and housed in a package as a product. A conventional mounting structure of such a light emitting element will be described with reference to the drawings. 5, FIG. 6, and FIG. 7 are perspective views showing a conventional light emitting element mounting structure. FIG. 8 is a side view of the main part showing the mounting position of the light emitting element.
[0003]
First, the configuration of a conventional light emitting element mounting structure will be described. In FIG. 5, 53 is a light emitting element, 51 is a heat radiation of a rectangular parallelepiped shape of about 1 to several tens of mm 3 formed by cutting, polishing, powder molding or the like using a metal material having high thermal conductivity such as copper or copper alloy. Block. When the light emitting element 53 is mounted on the block 51, the difference in coefficient of thermal expansion between the light emitting element 53 and the block 51 is so large that it cannot be ignored. Therefore, bonding is performed using soft solder such as an indium alloy to absorb the difference. ing. However, in this mount structure, since the solder is soft, the initial position accuracy is poor and a positional shift that cannot be ignored in the long term is caused. Therefore, it is difficult to improve the reliability of the light emitting element.
[0004]
The one shown in FIG. 6 is a highly reliable mount structure instead. In FIG. 6, reference numeral 52 denotes a mount made of a high thermal conductivity ceramic thin plate having a thermal expansion coefficient value close to that of the light emitting element 53, and is interposed between the light emitting element 53 and the block 51. The mount 52 is metallized with gold or the like for bonding the light emitting element 53 and the block 51. In mounting the light emitting element 53, first, the mount 52 and the block 51 are joined, and this is performed using a solder bond die bonder. In order to emit laser light in a desired direction, a predetermined assembly accuracy described later is required, and a dedicated high-precision die bonder having an image recognition device is used to mount the light emitting element 53 on the mount 52. As the connection material, a high heat conductive material such as a gold alloy is used.
[0005]
The alignment of the light emitting element 53 will be further described with reference to FIG. Reference numeral 54 denotes a package base on which the light emitting element 53 is mounted after the block 51 is assembled to the base 54. At this time, the position and inclination of the optical axis K must be within a predetermined accuracy with reference to the outer shape of the base 54. Since the optical axis K is substantially parallel to the outer shape of the light emitting element 53, first, the mount 52 is mounted on the block 51 with the mutual outer shape as a reference, and then the light emitting element 53 is mounted with the outer shape of the block 1 as a reference. Mount on. As shown in FIGS. 7 and 8, the assembly accuracy of the light emitting element 53 is generally within ± 30 μm for the position in the xyz axis direction and within ± 3 degrees for the inclination. So that the end face having a protrusion protrudes slightly (less than 40 μm) from the upper end of the mount 52. The mounting of the light emitting element 53 requires 3 to 30 seconds for each unit.
[0006]
[Problems to be solved by the invention]
However, in this mount structure, it is necessary to perform high-precision mounting twice between the block and the mount, and between the mount and the light-emitting element, and the light-emitting element is fixed over a long time using a dedicated high-precision die bonder. Implemented. The equipment cost and man-hours for that are large, and the product cost is increasing.
[0007]
The above-described invention has been made to solve such a conventional problem, and the object thereof is to provide a laser diode mounting structure that can contribute to reduction of man-hours and equipment costs by using a highly versatile device. And how to implement it.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention includes a laser diode and a laser diode, a mounting structure of a laser diode to be mounted on the heat sink block through a mount, where the length of the mounting shorter than the length of the laser diode In the mount structure for use, the mount is provided with a metallized pattern having a width equal to the width of the laser diode and a length equal to the length of the mount, and the metallized pattern has a lead-out pattern drawn out on both sides of the central portion. It is characterized by that.
[0011]
The invention of claim 2 is the invention according to claim 1, wherein the width of the lead pattern is equal to or less than half the length of the laser diode.
[0012]
The invention of claim 3 of the present invention, a laser diode, in the mounting method of the laser diode mount to be mounted on the heat sink block through a mount, it said shorter than the length length of the laser diode width and equal Shii width of the laser diode Chi di has lifting one metallized patterns lead pattern extending to both sides in the width direction from the central portion in the longitudinal direction, forming equal mount of the metallized patterns and length, the laser diode to the mounting , A step of forming a heat dissipation block, and a step of mounting a mount on the heat dissipation block.
[0013]
According to a fourth aspect of the present invention, in the third aspect of the present invention, in the step of mounting the laser diode on the mount, a step of placing a solder ribbon on the metallized pattern, and the laser diode on the solder ribbon And mounting the laser diode and heating the mount on which the laser diode and the solder ribbon are mounted.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a method for mounting a light emitting element. 2 is a perspective view showing a light emitting element mount structure according to an embodiment of the present invention, FIG. 3 is a perspective view of the light emitting element, and FIG. 4 is a perspective view of the mount.
[0015]
First, the configuration of the light emitting element mounting structure according to the embodiment of the present invention will be described.
In FIG. 2, 1 is the light emitting element shown in FIG. 3, and the outer shape is a rectangular parallelepiped whose length L in the optical axis K direction passing through the light emitting portion 1a is larger than the width W. Reference numeral 2 denotes a rectangular parallelepiped mount made of a high thermal conductive insulating material such as ceramics as shown in detail in FIG. 4, and the length L-α of one side is shorter than the length L of the light emitting element 1 by α (3 μm to 30 μm). Has been. Reference numeral 3 denotes a metallized pattern formed on the mount 2 in parallel to the outline, and has a width substantially equal to the width W of the light emitting element 1 and the same length as the mount 2, and the width from the substantially central portion in the length direction. A lead-out pattern 3a having an appropriate length with a width less than half of the length L is provided so as to extend on both sides in the direction. As shown in FIG. 2, the light-emitting element 1 has an end surface perpendicular to the optical axis protruding from the end surface of the mount 2 and mounted on the mount in advance, and then mounted on a heat dissipation block (not shown) and packaged together with other optical components such as a lens. Become a product.
[0016]
Next, a method for mounting the light emitting element will be described. In FIG. 1, 4 is a solder ribbon having substantially the same dimensions as the metallized pattern 3 and a thickness of 10 μm to 30 μm. After aligning and supplying the solder ribbon 4 to the metallized pattern 3 of the mount 2, the light emitting element 1 is placed on the solder ribbon 4 and heated without pressure in a non-oxidizing atmosphere such as nitrogen. As a result, the solder ribbon 4 is melted, and the lower surface of the light emitting element 1 and the metallized pattern 3 are wetted by the molten solder. A surface tension is generated in the molten solder, and a self-alignment action is performed to try to align the light-emitting element 1 with the position of the metallized pattern 3. Then, if it cools as it is, the light emitting element 1 can be positioned and soldered with high precision with respect to the outer shape of the mount.
[0017]
At this time, since the length L-α of the mount 2 is set to be shorter than the length L of the light emitting element 1, both ends of the light emitting element 1 are slightly smaller than the mount 2 as shown in FIG. / 2) Projects. Further, since the width of the metallized pattern 3 and the width W of the light emitting element 1 are formed to be substantially equal, the side edges of the two coincide with each other. Further, the amount of solder on the lower surface of the light emitting element 1 can be reduced by flowing the excess solder that has moved the positioning of the light emitting element 1 into the lead-out pattern 3a when the solder is melted.
[0018]
Next, the effect of this embodiment will be described. Since the self-alignment action by the molten solder works, the positioning accuracy as low as about 0.1 mm when the light emitting element 1 is mounted on the mount 2 by providing the metallized pattern 3 in parallel with the outer shape of the mount 2 with high accuracy. Only required. In addition, since the solder film under the light emitting element 1 can be thinned by the lead pattern 3a, the heat generated by the light emitting element 1 can be efficiently transmitted to the mount 2. This lead pattern is also used when wiring the electrodes of the light emitting element. Furthermore, since the light-emitting portion 1a has a structure that reliably protrudes from the end face of the mount 2, so-called “vignetting” in which the emitted light is reflected by the surface of the mount 2 does not occur.
[0019]
【The invention's effect】
As described above, according to the present invention, a metallized pattern is formed on a mount, a light emitting element is arranged with an accuracy of about 0.1 mm via a solder ribbon, and high-precision mounting is performed only by heating and cooling. Can be achieved with a general purpose device.
[0020]
In addition, when a light emitting element is mounted on a mount and solder is heated, a large number of pieces can be processed at the same time. Therefore, it is possible to secure mounting on a highly accurate mount with low man-hours.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a method for mounting a light emitting element submant according to an embodiment of the present invention;
FIG. 2 is a perspective view of a mount.
FIG. 3 is a perspective view of a light emitting element.
FIG. 4 is a perspective view of a mount.
FIG. 5 is a perspective view showing a conventional light emitting device mounting structure;
FIG. 6 is a perspective view showing another conventional mounting structure.
FIG. 7 is a perspective view showing a positioning reference of a light emitting element.
FIG. 8 is a side view of an essential part showing a mounting position of a light emitting element.
[Explanation of symbols]
1 Light-Emitting Element 2 Mount 3 Metallized Pattern 3a Drawer Pattern 4 Solder Ribbon

Claims (4)

A laser diode, a mounting structure of a laser diode to be mounted on the heat sink block through a mount, in the laser diode mount structure shorter than the length of the length of the mounting said laser diode, said mount, said laser A metallized pattern having a width equal to the width of the diode and a length equal to the length of the mount is provided, and the metallized pattern has a lead pattern extending from the center in the length direction to both sides in the width direction. Laser diode mounting structure. Leh Zada diode mount structure according to claim 1, wherein a width of said lead pattern is equal to or less than half the length of the laser diode. A laser diode, in the mounting method of the laser diode mount to be mounted on the heat sink block through a mount, Chi lifting the width and equal Shii width shorter than the length length of the laser diode and the laser diode, the central portion in the longitudinal direction a width direction of lifting one metallized patterns lead pattern extending to both sides from the formation forming the same mount of the metallized patterns and length, a step of mounting the laser diode to the mounting, the heat sink block process and method for mounting rail Zada diode mount, characterized in that a step of mounting a mounting on the heat sink block to. In the step of mounting a laser diode on the mount, a step of mounting a solder ribbon on the metallized pattern, a step of mounting the laser diode on the solder ribbon, and mounting the laser diode and the solder ribbon mounting method according to claim 3, wherein the laser Zada diode mount, characterized in that it comprises a step of heating the mounting that location.

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