JPH0693524B2 - Photoelectric conversion device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric conversion device that faces a light emitting element and holds an optical fiber on the same optical axis as that of the light emitting element by soldering using a chip carrier.

[Conventional technology]

FIG. 6 is a front view showing a conventional photoelectric conversion device. In the figure, 1 is a chip carrier having a pair of mounting bases 2 and 3 and a connecting portion 4 integrally connecting the mounting bases 2 and 3. A light emitting element (light emitting semiconductor element) 5 is held on a mounting base 2 which is one end of the chip carrier 1, and an optical fiber 6 is mounted on a mounting base 3 which is the other end of the chip carrier 1. It faces the light emitting portion 7 of the light emitting element 5 and is fixed by soldering so as to align the optical axis. Reference numeral 8 is a solder which is fixed to the mounting base 3 so as to wrap the optical fiber 6. The tip of the optical fiber 6 facing the light emitting element 5 has a spherical shape so that the emitted light 7a of the light emitting element 5 can be efficiently introduced and propagated into the optical fiber 6 which is an optical transmission path.

Further, in such an optical system, the coincidence or non-coincidence of the relative optical axes of the light emitting element 5 and the optical fiber 6 has a great influence on the optical transmission efficiency. The deviation may be 1 micrometer or less. Then, conventionally, when the optical fiber 6 is attached, generally, the solder is melted, the optical axis is aligned with the light emitting element 5 which is fixed in advance, and after the optical axis is aligned, it is cooled to cure the solder. I have to.

Here, although a method of using a resin for fixing the optical fiber 6 and the chip carrier 1 is conceivable, this method is inferior in temperature characteristics and long-term reliability as compared with a method of fixing by using solder.

When using solder to fix the optical fiber 6 and the chip carrier 1, it is desirable to coat the surface of the optical fiber 6 with a metal thin film in order to increase the adhesive force between the optical fiber 6 and the solder 8.

[Problems to be Solved by the Invention]

Since the conventional structure for mounting the optical fiber 6 on the photoelectric conversion device 1 is configured as described above, the solder 8 is cooled and solidified after the optical axis alignment work, and the optical fiber 6 is mounted on the mounting base portion 3.
However, since the solder 8 contracts when it further cools to room temperature after being solidified, the position of the optical fiber 6 fixed to the solder 8 moves from the position where the alignment adjustment is completed, and the light emitting element 5 and There is a problem that the coupling efficiency of the optical fiber 6 is greatly reduced.

Further, since the solder 8 shrinks uniformly, when the amount of solder 8 spread increases, the shrinking distance, that is, the moving distance Lha by which the optical fiber 6 moves due to the shrinking of the solder 8, is the optical axis of the optical fiber 6 and the chip carrier. proportional to the distance L ₁ between the first top surface. By the way, in order to find the position where the maximum coupling efficiency is obtained in the alignment adjustment of the axis of the optical fiber 6 and the optical axis of the light emitting element 5, a certain range in which the optical fiber 6 can be freely moved is required. Therefore, the distance L ₁ between the axis of the optical fiber 6 and the upper surface of the chip carrier 1 cannot be made smaller than the distance L 1imit that secures the above range.
(L ₁ L 1imit), when the conventional chip carrier is used, the optical fiber 6 due to contraction of the solder 8 proportional to this distance
There is a problem in that it is difficult to make the axial deviation of 1 μm or less as described above.

In addition, the chip carrier 1 is generally made of a material having good thermal conductivity in order to improve heat dissipation during operation of the light emitting element 5. The alignment of the optical fiber 6 is adjusted while operating the light emitting element 5. At this time, the temperature of the portion of the chip carrier 1 in contact with the solder 8 is higher than the melting point of the solder 8. In the conventional chip carrier shown in FIG. 5, the light emitting element 5 also has a high temperature. Operating the semiconductor element at a high temperature causes deterioration of the characteristics of the light emitting element 5.

Further, when the solder 8 is cooled and the optical fiber 6 is fixed, the chip carrier 1 is also cooled. However, the temperature difference between the mounting bases 2 and 3 causes distortion in the chip carrier 1 and There is a problem that the fiber 6 is misaligned with the light emitting element 5.

The present invention (first invention) has been made to solve the above-mentioned problems, and reduces the axial misalignment of the optical fiber due to the contraction of the solder with respect to the optical axis of the light emitting element as compared with the conventional one. It is an object of the present invention to obtain a photoelectric conversion device in which an optical fiber and a light emitting element can be efficiently coupled.

In addition to the above object, another invention (second invention) is to prevent the characteristic deterioration of the light emitting element by lowering the temperature of the light emitting element at the time of adjusting the alignment of the optical fiber and to prevent the distortion due to the temperature difference of the chip carrier. It is an object of the present invention to obtain a photoelectric conversion device capable of reducing the axial displacement of the optical fiber with respect to the light emitting element.

[Means for Solving the Problems]

A chip carrier according to the present invention has a base provided with a light emitting element at one end and a plate having an optical fiber fixed at the other end with a solder a, and the base is provided with the optical fiber fixed through the solder a and the plate. The plate is fixed to the base with solder b while keeping a distance smaller than the distance.

The second invention is the same as the first invention,
A heat insulating portion is provided on the base of the portion for fixing the plate.

[Action]

The chip carrier according to the present invention can minimize the positional deviation of the optical fiber due to the contraction of the solder which occurs when the optical fiber is fixed to the base.

Further, even when the base and the plate are fixed by soldering, the temperature rise of the base and the light emitting element can be suppressed as much as possible, and the axial displacement due to the strain of the base due to the temperature difference and the deterioration of the light emitting element can be prevented.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. Fifth
In the drawings, the same or corresponding parts are designated by the same reference numerals.
In the figure, 9 is a chip carrier according to the present invention, on a base 10 made of a material having good thermal conductivity,
It has a structure in which a flat metal plate (plate) 11 is fixed with solder b12.

FIG. 2 is a sectional view showing a state where the optical fiber is axially aligned and fixed using the chip carrier shown in FIG. base
The light emitting element 5 is fixed by soldering to one end side of 10 and
The metal plate 11 is fixed to the other end of the base 10 by solder b12. Then, on this metal plate 11, the base 10 and the metal plate 11
An optical transmission line is formed by using a larger amount of solder a8 than the solder b12 that fixes and. The optical fiber 6 is fixed.

That is, the solder a8 is fixed so that the distance between the upper surface of the metal plate 11 and the axis of the optical fiber 6 is larger than the distance between the upper surface of the base 10 and the lower surface of the metal plate 11.

Here, the surface of the optical fiber 6 is coated with a metal thin film in order to increase the adhesive force with the solder a8. In addition, the tip of the optical fiber 6 is the light emitted from the optical fiber 6 and the light emitting element 5.
It has been processed into a spherical shape in order to efficiently connect with 7a.

Next, the operation will be described. First, the alignment of the optical fiber 6 and the light emitting element 5 is adjusted in a state where the solder a8 is heated and melted, and the solder a8 is cooled and solidified so that the optical fiber 6 is cooled.
Is fixed to the metal plate 11. This optical fiber 6 is connected to the metal plate 11
In the process of fixing to, the solder a8 contracts while it solidifies and then cools to room temperature, so the axial center position of the optical fiber 6 with respect to the optical axis of the light emitting element 5 is the same as that of the optical fiber 6 and the light emitting element 5 as described above. Distance Lh from the position where the alignment adjustment is completed
An axis deviation of a (see FIG. 3) occurs.

Therefore, in order to reduce the axial deviation of the distance Lha, the solder b
Aligning the axis of the optical fiber 6 with the optical axis of the light emitting element 5 again so as to correct the deviation of the axis of the optical fiber 6 with respect to the optical axis of the light emitting element 5 in a state where 12 is heated and melted. Then, the solder b12 is cooled and solidified to fix the metal plate 11 on the base 10. At this time as well, the solder b12 contracts similarly, and the contraction of the solder b12 causes an axial deviation of the distance Lhb (see FIG. 3) from the axial center position of the optical fiber 6 with respect to the optical axis of the light emitting element 5.

As described above, the distance Lha of the axial misalignment of the optical fiber 6 from the optical axis of the light emitting element 5 due to the contraction of the solder a8 is the distance L ₂ from the axial center of the optical fiber 6 to the surface of the metal plate 11, that is, the light It is proportional to the above-mentioned distance L1imit, which is a range in which the optical fiber 6 can be freely moved in the axial adjustment of the axis of the fiber 6 and the optical axis of the light emitting element 5. On the other hand, the distance Lhb of the axial misalignment of the optical fiber 6 from the optical axis of the light emitting element 5 due to the contraction of the solder b12 is the distance L ₃ between the surface of the metal plate 11 and the surface of the base 10, that is, the optical fiber 6 It is proportional to the distance that secures a range in which the metal plate 11 can be freely moved in order to adjust the axis and the optical axis of the light emitting element 5 in alignment.

Here, the distance L ₃ between the surface of the metal plate 11 and the surface of the base 10 is provided for the purpose of correcting the axial deviation of the distance Lha of the optical fiber 6 by the metal plate 11, and therefore the axis of the optical fiber 6 is adjusted. And L1imit between the optical axis of the metal plate 11 and the optical axis.

Therefore, the axial misalignment of the optical fiber 6 with respect to the optical axis of the light emitting element 5 when the optical fiber 6 is fixed using the conventional chip carrier 1 is the length of the distance Lha as described above. The axial misalignment distance Lhb when the optical fiber 6 is fixed using the chip carrier 9 is the conventional axial misalignment distance L.
It can be made sufficiently smaller than ha.

Next, an embodiment of the second invention will be described with reference to FIG.
A case where a glass plate is used as the heat insulating material used in this example will be described. Reference numeral 13 denotes a chip carrier according to the second invention, which is provided with a glass plate 14 which is a heat insulating material in addition to the structure of the chip carrier 9 of the first invention described above. Fixed on and soldered onto the glass plate 14.
The structure is such that the metal plate 11 is fixed via b12. Both sides of this glass plate 14 are for increasing the adhesive force between the glass plate 14 and the metal plate 11 and the adhesive force between the glass plate 14 and the base 10.
It goes without saying that a metal thin film is coated.

FIG. 5 is an explanatory view showing a state in which the optical fiber 6 is axially aligned and fixed using the chip carrier 13 according to the second invention. The glass plate 14 is fixed in advance on the base 10, and the optical fiber 6 and the metal plate 11 are fixed in advance by solder a8 as described above. The misalignment of the optical fiber 6 caused by the fixing of the metal plate 11 and the glass plate 14 with the solder b12 causes the above-mentioned metal plate 11
Similar to the axial misalignment of the optical fiber 6 caused by fixing the solder b12 to the base 10 using the solder b12, the optical fiber 6 caused by the contraction of the solder
The axial misalignment can be made sufficiently smaller than the axial misalignment of the optical fiber 6 when the conventional chip carrier 1 is used.

In addition, while the solder b12 between the metal plate 11 and the glass plate 14 is heated and melted, the upper surface side of the glass plate 14 has a high temperature, but since the glass has extremely low thermal conductivity,
The temperature rise on the lower surface side of the glass plate 14 in contact with the base 10 is extremely small. Therefore, even when the solder b12 is melted, the temperature rise of the base 10 and the light emitting element 5 is small, the characteristic of the light emitting element 5 is deteriorated, and the temperature difference between the one end and the other end of the base 10 occurs. There is no risk of misalignment of the optical fiber 6 due to distortion.

In the above embodiment, the case where the flat plate is the metal plate is described, but the same effect of the invention can be obtained when the glass plate or the ceramic plate is used.

Further, in the above-described embodiment, the case where the glass plate is used as the heat insulating material has been described, but the same effect of the invention can be obtained when another heat insulating material is used.

Further, in the above embodiment, the case where the light emitted from the light emitting element is directly coupled to the optical fiber has been described, but the same effect of the invention can be obtained even when an optical system such as a lens is arranged between the light emitting element and the optical fiber. can get.

Further, in the above embodiment, the solder a for fixing the optical fiber and the plate to be used has a higher melting point than the solder for fixing the base and the plate, so that the axial misalignment can be effectively prevented.

〔The invention's effect〕

As described above, according to the present invention, the chip carrier is formed by the base to which the light emitting element is directly attached to one end and the plate soldered and fixed to the other end of the base, and the plate and the optical transmission are formed. The distance between the solder layer that fixes the base and the plate is smaller than the distance between the solder layer that fixes the path and the solder layer that fixes the base and the plate by shrinking the solder layer that fixes the plate and the optical transmission path. Since the correction is performed by the above, it is possible to minimize the positional deviation of the optical transmission line due to the contraction of the solder when fixing the optical transmission line to the chip carrier. Further, since the correction is performed by the solder layer, the correction accuracy does not depend on the linear expansion coefficient of the plate, and the material can be easily selected without using an expensive material for the plate. Furthermore, since the light emitting element is configured to be directly attached to one end of the base, it is possible to simplify the steps of configuration and manufacturing, and to easily adjust the alignment between the light emitting element and the optical transmission path. Moreover, there is an effect that it can be performed accurately.

According to another invention, in addition to the configuration of the above invention, the heat insulating portion is provided between the base and the plate. Therefore, in addition to the effects of the above invention, the base and plate of the chip carrier are provided. When fixing with solder, it is possible to suppress the temperature rise of the light emitting element as much as possible and prevent the light emitting element from deteriorating, and it is possible to prevent the misalignment between the light emitting element and the optical transmission line due to the distortion of the base due to the temperature difference. is there.

[Brief description of drawings]

1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view showing a state in which an optical fiber is axially aligned and fixed using the chip carrier according to the present invention, and FIG. 3 is a sectional view of FIG. FIG. 4 is a state explanatory view for explaining the action, FIG. 4 is a sectional view showing an embodiment of another invention of the present invention, and FIG. 5 is an optical fiber axis using a chip carrier according to another invention of the present invention. FIG. 6 is a sectional view showing a state where the optical fibers are axially aligned and fixed using a conventional chip carrier. In the figure, 1 is a conventional chip carrier, 5 is a light emitting (semiconductor) element, 6 is an optical fiber, 8 is a solder a, 9 and 13 are chip carriers according to the present invention, 10 is a base, 11 is a plate,
12 is a solder b, and 14 is a heat insulating portion. In the drawings, the same or corresponding parts are designated by the same reference numerals.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Takei 325 Kamimachiya, Kamakura City, Kanagawa Mitsubishi Electric Corporation Information & Electronics Laboratory (56) References JP-A-57-138191 (JP, A) JP-A-60 -26909 (JP, A)

Claims (8)

[Claims] 1. A photoelectric conversion device in which the light emitting element and the optical transmission path are fixed by using solder so as to face each other on a chip carrier so that the axis of the optical transmission path is aligned with the optical axis of the light emitting element. In the above, the chip carrier is constituted by a base having the light emitting element directly attached to one end and a plate soldered and fixed to the other end of the base, and the optical transmission line is soldered and fixed to the plate. At the same time, the distance between the solder layer that fixes the base and the plate is smaller than the distance between the solder layer that fixes the plate and the optical transmission path, and the contraction of the solder layer that fixes the plate and the optical transmission path is reduced by the base. A photoelectric conversion device characterized in that correction is made by a solder layer for fixing the plate and the plate. 2. The photoelectric conversion device according to claim 1, wherein a metal plate is used as the plate. 3. The photoelectric conversion device according to claim 1, wherein a ceramic plate is used as the plate. 4. The photoelectric conversion device according to claim 1, wherein a glass plate coated with a metal thin film is used as the plate. 5. The photoelectric device according to claim 1, wherein the solder for fixing the optical transmission line and the plate has a higher melting point than the solder for fixing the base and the plate. Converter. 6. A photoelectric conversion device in which the light emitting element and the optical transmission path are fixed by using solder so as to oppose each other on a chip carrier so that the axis of the optical transmission path is aligned with the optical axis of the light emitting element. In the above, a base having the light emitting element directly attached to one end thereof, and a heat insulating portion attached to the other end of the base,
The chip carrier is constituted by a plate soldered and fixed on the heat insulating portion, and the optical transmission line is fixed by soldering on the plate, and the distance between the solder layers fixing the plate and the optical transmission line is determined. The distance between the solder layer that fixes the heat insulating section and the plate is reduced, and the shrinkage of the solder layer that fixes the plate and the optical transmission line is corrected by the solder layer that fixes the heat insulating section and the plate. Photoelectric conversion device. 7. The photoelectric conversion device according to claim 6, wherein a heat insulating material coated with a metal thin film is used as the heat insulating portion. 8. The solder for fixing the optical transmission line and the plate has a melting point higher than that of the solder for fixing the heat insulating part and the plate. Photoelectric conversion device.