JPH0536181Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a light-receiving module in which a light-receiving element is housed in a metal box.

B. Prior Art Conventionally, the light receiving module has been housed in a shielding metal box together with the substrate containing the light receiving element because the output of the light receiving element is weak. And Utsukai Showa 61-
As shown in Publication No. 63879 and its specification, the metal box body is fixed by caulking, but it is extremely difficult to assemble.

To explain in more detail, conventionally, as shown in FIG. 3, a metal box 13 with one side open is prepared, a unit body formed by assembling a substrate 11a with a light receiving element 12 fixed thereto and a substrate 11b with an integrated circuit element 15 fixed thereto is inserted into the metal box, the open side of the metal box 13 is covered with a metal plate 18, and the metal box 13 is pressed against the tabs 13a and 13b.
The metal plate 18 was fixed by bending the a. However, each component part is small, with each side measuring at most 20 mm, and has a directional property. Moreover, if there is too much difference in size between the unit and the box, it will cause a decrease in the amount of light received due to rattling and short circuit accidents, so the outermost circumference of the unit and the inside size of the box are made as close as possible, making the above assembly work complicated. Furthermore, if the metal plate 18 accidentally falls into the box, it may damage the wiring pattern, etc.

C. Problems that the invention aims to solve This invention was made in consideration of the above points.
The present invention provides a light receiving module that is easy to assemble and has stable characteristics.

D. Means for solving the problem The present invention is constructed so that the surface of the box that corresponds to the lid (hereinafter referred to as the bottom surface) is connected to one side and a lid is formed by bending, and the side opposite to the connected side of the bottom surface is A tongue piece is provided on the outside of the box body to engage with another side surface, and a tongue piece is provided on the other side to engage with another side face on the inside of the box body.

From this, if we consider the directionality only when inserting a substrate unit with a light receiving element into a metal box,
After that, just fold the bottom and you can store the unit without any wobble.

F. Embodiment FIG. 1 is a sectional view of a light receiving module according to an embodiment of the present invention, and FIG. 2 is a perspective view of a metal box used therein. In these figures, 1 is a substrate having a light receiving element 2, and 3 is a metal box which houses the substrate 1 and is bent into a rectangular parallelepiped shape. This metal box is made by cutting out and bending a metal plate in the form of a roughly cross-shaped dice development, and the bottom surface 31 is 1
It is connected to the side surface 32 and has a tongue piece 31l that engages with the other side surface 34 on the outside of the box body on the side 31c opposite to the connected side 31a, and the other side 31
b, 31d on the inside of the box, the other side 33,
It has tongue sides 312, 312 that lock with 35.

The light receiving module will be explained in more detail.

Other electronic components 4 such as capacitors of the light receiving element 2, a circuit element (amplifier) 5 for amplifying the output of the light receiving element, and (power/output) terminals 6 are fixed to the substrate 1. Of these, the light-receiving surface of the light-receiving element 2 and its both sides (Figure 1 is a cross-sectional view, so only one side is shown)
The components are arranged so that one side of the electronic components 4 arranged on the surface of the electronic component 4 forms a substantially flat surface. This is necessary to enhance the shielding effect when electromagnetic noise is strong, but if you put a mesh in the light receiving window 1321 as shown in Figure 3, the optical signal will also be attenuated, and if you try to install an electromagnetic wave cut film, the light receiving module will be in use. This is undesirable because the film curls and is no longer parallel to the light-receiving surface, causing light reflection or separating the film from the light-receiving surface. On the other hand, if the light-receiving surface and the electronic component surface are arranged so as to support one plane and face one inner wall of the metal box, simply inserting the electromagnetic wave cut film 7 into the gap will sandwich the film in a flat plate shape. . Regarding the arrangement of other components, it is best to place the light receiving element 2 and the terminal 6 far apart as a noise countermeasure, and the output of the circuit element 5 and the terminal 6 should be placed far apart.
It is preferable that the wiring be as short as possible.

Next, the metal box body is formed to constitute a rectangular parallelepiped with a bottom surface of about 16 x 14 mm and a height of about 13 mm, and the tongue piece 31
1,312 may be locked using the protrusion 36 and the through hole 37. Further, it is preferable to provide claws 38 and cutouts 39 to prevent the substrate 1 from wobbling, but it is more preferable to provide an abutment piece 312a at the tip of the tongue piece 312 that goes inside the box to fix the substrate 1. In addition, in order to prevent the tongues 311 and 312 from damaging the terminals 6 and the wiring pattern of the board when covering the bottom surface 31 and the mutual arrangement of the components on the board mentioned above, the light receiving window 321 is placed on the connected side surface of the bottom surface 31. 32, terminal window 31
3 is preferably provided near the side 31c of the bottom surface 31.

Effects of the invention As described above, each part is small and has a directionality in assembly, and even if the difference between the unit dimensions and the box dimensions is small, the assembly is not complicated. In addition, it is possible to securely fix the unit, fix the bottom surface, and prevent the film from curling when using the film without damaging it.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a light receiving module according to an embodiment of the present invention, and Fig. 2 is a perspective view of a metal box used therein.
FIG. 3 is a sectional view of a conventional light receiving module. 1... Board, 2... Light receiving element, 3... Metal box.

Claims (1)

[Scope of utility model registration request] In a light-receiving module that includes a substrate having a light-receiving element and a metal box that houses the substrate and is bent into a rectangular parallelepiped shape, the bottom surface of the metal box is connected to one side surface, and the connected side is A light receiving device characterized by having a tongue piece on the side opposite to the body that engages with another side surface on the outside of the box body, and a tongue piece on the other side that engages with another side face on the inside of the box body. Module.