JPH05145213A - Mounting method of light module - Google Patents

Abstract

PURPOSE:To ensure a long-term reliability after a light module is mounted, by electrically connecting the light module and a circuit board through clamping the lead pin of the light module by elastic members mounted on the circuit board. CONSTITUTION:A lead pin 5 on a light module 1 is clamped by a pair of elastic members 9 fixed on a circuit board 4 and the light module 1 and circuit board 4 are connected by these elastic members 9. In this manner, the mounting work of the light module 1 can be improved. Also, a stress generated between the light module 1 and circuit board 4 is absorbed by the elastic members 9 so that the long-term reliability of arm apparatus using the light module and the reliability against a physical disturbance are improved. Further, loose lead wire, etc., are not used so that the increase of inductance in a terminal area can be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module mounting method. More specifically, the present invention relates to a novel method for mounting an optical module on a circuit board on which various electronic circuits are mounted.

[0002]

2. Description of the Related Art An optical module is equipped with a light-emitting element which is an electro-optical conversion element and / or a light-receiving element which is an opto-electrical conversion element, and by connecting to a necessary electronic circuit according to the application, Used as a member for optical data links.

Since an optical module and an electronic circuit are generally different from each other in manufacturing process and form, when manufacturing equipment using the optical module, at least the individually manufactured optical module and electronic circuit are electrically connected. A process of connecting them physically is required.

FIGS. 4 (a) to 4 (c) are views showing a method of mounting an optical module in an apparatus using the optical module as described above. Incidentally, the electronic circuit side is represented by an end portion of the substrate for convenience.

In each drawing, an optical module 1 is fixed to a side surface of a housing 2 of a device with a screw 3. On the other hand, the board 4 on which the electronic circuit is mounted is assumed to be fixed to the bottom surface of the housing 2 with a screw or an adhesive agent (not shown).

In the method shown in FIG. 4 (a), the substrate 4 is mounted on the spacer 2a formed on the bottom surface of the housing 2, so that the mounting surface of the substrate 4 and the lead pin provided on the rear side of the optical module 1 are mounted. The lead pins 5 are fixed to the wiring pads on the substrate 4 with solder 6 after the heights of the lead pins 5 are substantially the same.

Further, in the method shown in FIG. 4 (b), the wiring pad on the substrate 4 fixed on the bottom surface of the housing 2 and the lead pin 5 provided on the rear side of the optical module 1 are connected to the plated wire 7.
Are connected through. Here, both ends of the plated wire 7 are
Each is fixed to the lead pin 5 or the wiring pad by the solder 6.

Further, in the method shown in FIG. 4 (c), the wiring pads on the substrate 4 fixed to the bottom surface of the housing 2 and the lead pins 5 provided at the rear of the optical module 1 are connected by the bonding wires 8. Connected through. Both ends of the bonding 8 are fixed to the lead pins 5 or the wiring pads by welding by applying heat or ultrasonic waves.

[0009]

The conventional methods shown in FIG. 4 have the following problems.

The optical module manufactured by the method shown in FIG. 4 (a) changes the relative position between the optical module 1 and the substrate 4 due to residual thermal stress generated during soldering or vibration during use. Therefore, stress may be applied to the connection portion.
The action of such stress causes peeling of the soldered portion and the wiring pad on the substrate, which may lead to breakage of these portions. Therefore, the device having the configuration shown in FIG. 4 (a) is inferior in long-term reliability.

In the method shown in FIG. 4 (b), the number of places where soldering has to be performed is doubled and the soldering has to be performed within a narrow work area. There is a problem that the sex is extremely bad. Further, in such a method, since an elongated lead wire has to be used, the inductance in the connection portion increases, and especially when an optical element such as a laser diode having a small electric capacity is used or the signal transmission speed is low. If it exceeds 100 Mbps, there is a problem that the characteristics of the optical data link deteriorate.

The method shown in FIG. 4 (c) requires a special structure and layout capable of applying heat and ultrasonic waves for wire bonding. Further, since the shape and material of the pads on the substrate and the lead pins of the optical module are limited, there are problems that design restrictions are large, component costs are high, and it is difficult to miniaturize the product.

Therefore, the present invention solves the above-mentioned problems of the prior art, is excellent in productivity in terms of manufacturing cost and workability, and can secure long-term reliability after mounting an optical module. It is an object of the present invention to provide a mounting method of an optical module having a new structure.

[0014]

That is, according to the present invention,
A method of connecting an optical module and a circuit board in a step of manufacturing an optical module device in which a circuit board on which an electronic circuit is mounted and an optical module on which an optical element is mounted are integrally formed. An optical module mounting method is provided, which includes a step of electrically connecting the optical module and the circuit board by clamping a lead pin of the optical module by an elastic member mounted on the optical module. ..

[0015]

The mounting method of the optical module according to the present invention is characterized mainly in that the elastic module mounted on the circuit board supports the optical module by physically gripping the lead pin.

That is, in the conventional optical module device, the lead pins of the optical module are connected to the circuit board by soldering or bonding. However, in such a method, there is a problem that stress is generated in the joint portion due to a change in the relative position between the optical module and the circuit board, residual stress caused by thermal stress, etc., and long-term reliability is degraded. Further, a method of interposing a flexible connecting member between the lead pin and the circuit board in order to absorb such stress is not practical because the manufacturing process is increased.

On the other hand, in the optical module mounting method according to the present invention, since the circuit board and the optical module are connected by clamping the lead pins of the optical module with the elastic member, the optical module is not changed. Not only can it be absorbed by the elastic member, but even when a displacement exceeding a predetermined limit occurs, the lead pin simply falls off, and permanent damage to the optical module or circuit board is avoided. Further, the mounting of the optical module is performed only by inserting the lead pin into the elastic member, so that the mounting process is simplified, thermal stress is not generated, and the layout is limited.

Hereinafter, the present invention will be described in more detail with reference to examples, but the following disclosure is merely an example of the present invention and does not limit the technical scope of the present invention.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram specifically showing a method of mounting an optical module according to the present invention. The same members as those in the conventional example shown in FIG. 4 are designated by the same reference numerals.

As shown in the figure, in this device, the lead pin 5 of the optical module 1 is clamped by the pair of elastic members 9 fixed on the circuit board 4, and the optical module 1 is clamped by the elastic member 5. And the circuit board 4 are connected.

FIG. 2 is a sectional view showing the shape and mounting structure of the elastic member 9 in the optical module device shown in FIG. 1. FIG. 2 (a) shows the X section in FIG. Shows the Y section in FIG. 1, respectively.

As shown in the figure, the elastic member 9 is a clamp formed by bending a leg portion 9a inserted into a through hole formed in the circuit board 4 and an end portion of the member 9 at different positions. It is composed of a part 9b. Also,
The legs 9a are fixed in the through holes 4a of the circuit board 4 by soldering or the like.

The elastic member 9 can be mounted by the same method as that for mounting an ordinary element on a substrate. That is, after inserting the leg portion 9a of the elastic member 9 into the through hole 4a of the circuit board 4,
It can be easily fixed from the back surface of the circuit board 4 with solder or the like.

According to a preferred embodiment of the present invention, for example, when the thickness of the lead pin 5 of the optical module used here is 0.45 mmφ, the clamp strength of the lead pin by the elastic member 9 is 300 gf. The following is preferable. The reason is that when the clamp strength is larger than this, when the relative position between the optical module 1 and the circuit board 4 changes for some reason, the mounting portion of the lead pin 5 or the mounting portion of the elastic member 9 itself is damaged. This is because such stress is generated.

Further, in order to improve the wettability of solder when it is mounted on the circuit board 4 and to prevent conduction failure due to surface oxidation, the surface of the elastic member 9 is made of Ni and Au.
It is desirable to plate with.

According to the connection method of the present invention as described above, since the lead pin 5 of the optical module 1 and the circuit board 4 are connected via the elastic member 9, the optical module 1
Even if the change occurs, the lead pin 5 and the circuit board 4 are not applied with excessive stress. That is, the displacement of the optical module 1 is absorbed by the deformation of the elastic member 9 or the sliding of the elastic member 9 and the lead pin 5.

Further, in the mounting process of the optical module according to this method, since the lead pin 5 is simply inserted into the elastic member 9, no complicated work such as soldering or bonding is required. Therefore, it is not necessary to design the layout in consideration of the mounting process.

Further, since the optical module 1 can be easily removed, the circuit board 4 and the optical module 1 can be easily replaced, and the device using the optical module can be easily repaired and maintained.

FIG. 3 is a diagram showing another aspect of the mounting method according to the present invention. The same members as those shown in FIG. 1 are designated by the same reference numerals.

As shown in the figure, the optical module used here has six lead pins 5. Therefore,
Six elastic members 9 are also mounted on the circuit board 4 side, and these elastic members 9 are covered with and integrated with a resin cover 10 which is an insulating material. The resin cover 10 has, for example, six holes formed at predetermined positions to facilitate insertion of the plurality of lead pins 5 into the elastic member at once.

[0031]

As described above, according to the optical module mounting method of the present invention, the workability of the optical module mounting process is remarkably improved by using the elastic member for clamping the lead pin of the optical module. can do.

Since the stress generated between the mounted optical module and the circuit board is absorbed by the elastic member, the long-term reliability of the device using the optical module and the reliability against physical disturbance are also improved.

Further, unlike the conventional mounting method, since a loose lead wire or the like is not used, it is possible to avoid an increase in inductance in the connection portion.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a method of mounting an optical module according to the present invention.

FIG. 2 is a diagram showing a method of mounting an elastic member used in the method shown in FIG.

FIG. 3 is a diagram showing another aspect of the mounting method according to the present invention.

FIG. 4 is a diagram showing a conventional method of mounting an optical module.

[Explanation of symbols]

1 ... Optical module, 2 ... Housing, 3 ... Screw,
4 ... Board, 5, 9 ... Lead pin,
6 ... Solder, 7 ... Plating wire, 8 ... Bonding wire, 9 ... Elastic member, 10 ...
resin

Claims (1)

[Claims] 1. A method of connecting an optical module and a circuit board in a step of manufacturing an optical module device in which a circuit board on which an electronic circuit is mounted and an optical module on which an optical element is mounted are integrally formed. The mounting of an optical module, including the step of electrically connecting the optical module and the circuit board by clamping a lead pin of the optical module with an elastic member mounted on the circuit board. Method.