JPH0661522A - Reflection type photocoupler - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a reflection type optical coupling device that enables surface mounting, is thin, and requires a small mounting area. [Structure] The mounting pattern 12 is provided on the upper surface of the printed circuit board 11.
Electrodes 14a, 14b, 15a and 15b are formed on the lower surfaces of a and 12b and connection patterns 13a and 13b, and the upper and lower patterns are connected through through holes 16. The light emitting element 19 is mounted on the light emitting side mounting pattern 12a, and the light receiving element 21 is mounted on the light receiving side mounting pattern 12b.
Is mounted and each element is connected to the connection patterns 13a and 13b through the gold wires 20 and 22. The mounting recesses 18a and 18b are filled with translucent sealing resins 23a and 23b. To form the mounting recesses 18a and 18b, the through hole 17 is formed in the printed circuit board 11.
The recess forming substrate 17 on which a and 17b are formed is superposed and integrated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflective type which detects the presence or absence of an object to be detected without contact depending on whether the light emitted from the light emitting element is incident on the light receiving element through the reflection on the object to be detected. The present invention relates to an optical coupling device (photo sensor).

[0002]

2. Description of the Related Art FIG. 9 is a perspective view showing the structure of a conventional general reflection type optical coupling device, and FIG. 10 is a sectional view thereof. In the figure, 1 is a light emitting element, 2 is a light receiving element, 3a and 3b are gold wires, 4a and 4b are element mounting lead frames, 5a and 5a.
b is a lead frame for connection, 6 is a package, 6a is a partition wall in the package 6, 7a and 7b are mounting recesses formed by the package 6, and 8a and 8b are transparent holes filled in the mounting recesses 7a and 7b. It is an optical sealing resin.

A manufacturing process of the reflection type optical coupling device of FIGS. 9 and 10 will be described. The package 6 having the partition wall 6a is formed on the lead frames 4a, 4b, 5a, 5b by insert molding or the like. The light emitting element 1 is die-bonded to the element mounting lead frame 4a in the mounting recess 7a of the package 6, and the light receiving element 2 is die bonded to the element mounting lead frame 4b in the mounting recess 7b. Silver paste is used for these die bonds. Next, in order to achieve electrical conduction, the light emitting element 1
Connecting lead frame 5a facing each other via the gold wire 3a
At the same time, the light receiving element 2 is connected to the opposing lead frame 5b via the gold wire 3b. These wire bonds are also performed in the mounting recesses 7a and 7b.

Light-emitting element 1 is prepared by injecting translucent sealing resin 8a, 8b such as epoxy resin into mounting recesses 7a, 7b.
The gold wire 3a and the light receiving element 2 and the gold wire 3b are sealed. The lead frames 4a, 4b, 5a, 5b are bent into an L shape.

As shown in FIG. 11, the lead frame 4
There is also known a reflection type optical coupling device in which a, 4b, 5a and 5b are bent in a hook shape to form a surface mounting type. In addition, FIG.
As shown in, the lead frames 4a, 4b, 5a, 5b
There is also known a reflection-type optical coupling device of a type in which is folded in two steps and wound around the back side of the package 6.

[0006]

In any of the above-mentioned conventional examples, since the package 6 is formed on the lead frame so as to enclose the lead frames 4a, 4b, 5a, 5b, the strength or the molding is improved. Due to the flowability of the resin, the thickness of the bottom plate portion 6b of the package 6 cannot be reduced to a certain value or less, and there is a certain limit in reducing the thickness. In particular, in the case of FIGS. 9 and 10, the lead frame is L
Since it is in the shape of a letter, there is a drawback that the height becomes large when mounted on a printed circuit board.

In the case of FIG. 11, although it can be surface-mounted on the printed circuit board, there is a drawback that the mounting area becomes large because the lead frames 4a, 4b, 5a, 5b extend laterally outward. In the case of FIG. 12, the mounting area is small, but the overall thickness is large.

The present invention was devised in view of the above circumstances, and an object thereof is to provide a reflection type optical coupling device which can be surface-mounted and which is thin and requires a small mounting area. .

[0009]

A first reflective optical coupling device according to the present invention is a reflective optical coupling device in which a light emitting element and a light receiving element are arranged side by side on a printed circuit board so as to be optically coupled to each other. , A light emitting side mounting pattern and a wiring pattern and a light receiving side mounting pattern and a wiring pattern are formed on the upper surface of the printed circuit board, and electrodes are provided on the lower surface in correspondence with the respective mounting patterns and wiring patterns. A pattern is formed and each mounting pattern and each electrode pattern are electrically connected through a through hole, and each wiring pattern and each electrode pattern are electrically connected through a through hole. A pair of through-holes corresponding to the light-emitting side mounting pattern and the wiring pattern separated by a partition wall and the light-receiving side mounting pattern and the wiring pattern. A light-shielding recess forming substrate having a through hole formed on the printed circuit board so that each through hole forms a mounting recess on each of the light receiving and emitting sides. It is a thing.

A second reflection type optical coupling device according to the present invention is
In a reflection type optical coupling device in which a light emitting element and a light receiving element are juxtaposed on a printed circuit board so as to be optically coupled,
A light emitting side mounting pattern and a wiring pattern and a light receiving side mounting pattern and a wiring pattern are formed on the upper surface of the printed circuit board, and an electrode pattern corresponding to each of the mounting pattern and each wiring pattern on the lower surface. Is formed and each mounting pattern and each electrode pattern are electrically connected through a through hole, and each wiring pattern and each electrode pattern are electrically connected through a through hole, By molding a light-shielding resin on the printed circuit board, a mounting recess corresponding to the mounting pattern and the wiring pattern on the light emitting side, and a mount corresponding to the mounting pattern and the wiring pattern on the light receiving side A package having a mounting recess and a partition wall separating the mounting recesses from each other is integrated with the printed circuit board. Is shall.

[0011]

[Function] Since the mounting patterns and the wiring patterns on the upper surface are electrically connected to the electrode patterns on the lower surface through the through holes, the surface mounting is of course possible.
The external size of the printed circuit board becomes the mounting area as it is, and the mounting area can be reduced. In order to form the mounting recess, in the first reflective optical coupling device, the recess forming substrate is superposed on the printed circuit board, or in the second reflective optical coupling device, the package is integrally molded on the printed circuit board. However, the thickness of the lower side of the mounting recess is only the thickness of the printed circuit board including the pattern thickness, and the thickness can be sufficiently reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a reflection type optical coupling device (photosensor) according to the present invention will be described below in detail with reference to the drawings.

First Embodiment FIG. 1 is a perspective view of the reflective optical coupling device according to the first embodiment during the assembling process, and FIG. 2 is a sectional view showing the structure after assembly.

On the upper surface of the printed circuit board 11, a light emitting side mounting pattern 12a and a wiring pattern 13a and a light receiving side mounting pattern 12b and a wiring pattern 1 are formed.
3b is formed, and each mounting pattern 12a, 12b and each connection pattern 13 is formed on the lower surface thereof.
The electrode pattern 14 corresponding to each of a and 13b
a, 14b, 15a and 15b are formed, and the light emitting side mounting pattern 12a and the electrode pattern 14a, which correspond to each other in the vertical direction, the light receiving side mounting pattern 12b and the electrode pattern 14b, and the light emitting side connection pattern 13a. The electrode pattern 15a, the light-receiving side wiring pattern 13b, and the electrode pattern 15b are electrically connected to each other through through holes 16.

Two light-shielding recess-forming substrates 17 are prepared in which the through-holes 17a and 17b for forming the recesses are formed so as to separate the partition wall 17c. These two recess forming substrates 17 have exactly the same shape. The through hole 17a on the light emitting side corresponds to the mounting pattern 12a on the light emitting side and the wiring pattern 13a, and the through hole 17b on the light receiving side corresponds to the mounting pattern 12b on the light receiving side and the wiring pattern 13b. These two recess forming substrates 17 are laminated and bonded to each other and also to the upper surface of the printed circuit board 11. As a result, the through hole 17a forms the light emitting side mounting recess 18a, and the through hole 17b forms the light receiving side mounting recess 18b.
In addition, when the mounting recesses 18a and 18b having a predetermined depth can be formed by one recess forming substrate 17, the recess forming substrate 17 of the second layer may be omitted. If the recess forming substrate is thin, a large number of layers may be stacked.

In the mounting recess 18a on the light emitting side, the light emitting element 19 is die-bonded onto the mounting pattern 12a on the light emitting side via silver paste or the like, and the light emitting element 19 and the connecting pattern 13a are connected to the gold wire 20. It is electrically connected via. Similarly, in the mounting recess 18b on the light receiving side, the light receiving element 21 is die-bonded onto the mounting pattern 12b on the light receiving side via silver paste or the like, and the light receiving element 21 and the connection pattern 13b are connected to the gold wire 22. It is electrically connected via.

Then, the recesses 18a and 18b for both mounts
Translucent sealing resin 23a, 23b such as epoxy resin
The reflective optical coupling device A is manufactured by filling and solidifying.

In the structure of the conventional example, the lead frames 4a,
The thickness of 4b, 5a, 5b is 0.15 if it is thinner from the viewpoint of strength.
The limit is about mm, and the thickness of the bottom plate portion 6b of the package 6 below the lead frame is about 0.3 mm at the thinner side from the viewpoint of resin flowability and strength at the time of molding, and the recess 7a, The lower limit of the thickness of 7b was about 0.45 mm. However, in the case of the structure of the present invention, when the printed circuit board 11 is, for example, a glass epoxy substrate, the thickness of the printed circuit board 11 can be about 0.1 mm including the pattern thickness, and the mounting recess 18a,
The lower thickness of 18b is about 0.1 mm, which is 1/5 to 1/4 of the thickness of the conventional example, which is considerably thin.

Then, on the lower surface of the printed circuit board 11, an electrode pattern 14 which is conducted through a through hole 16 is formed.
Since a, 14b, 15a, and 15b are formed, it goes without saying that surface mounting is possible, and the printed circuit board 1
The size of the outer shape of 1 becomes the mounting area as it is, and the mounting area can be reduced as compared with the conventional example having the lead frame. Further, since there is no lead frame, steps such as bending and cutting of the lead frame are unnecessary, and the cost can be reduced accordingly.

3 and 4 show an application of the above embodiment in the case of manufacturing a plurality of reflection type optical coupling devices A in a lump, and after filling the translucent sealing resins 23a and 23b,
The cutting is performed by a dicing machine or the like along the chain line shown in the figure. By adopting this mass production method, rationalization in production can be achieved.

Second Embodiment FIG. 5 is a sectional view of a reflection type optical coupling device according to a second embodiment, and FIG. 6 is a perspective view. The structure of the printed board 11 is similar to that of the first embodiment. The package 31 is integrated with the printed board 11 by transfer-molding or injection-molding a light-shielding resin on the printed board 11.
The package 31 has a mounting recess 31 corresponding to the mounting pattern 12a on the light emitting side and the connection pattern 13a.
a and a mounting recess 31b corresponding to the light-receiving side mounting pattern 12b and the connection pattern 13b are formed in a state separated by a partition wall 31c. The printed board 11 may be a hard board or a flexible board. Since other configurations are the same as those of the first embodiment, corresponding or corresponding portions will be denoted by the same reference numerals and description thereof will be omitted.

Third Embodiment FIG. 7 is a sectional view of a reflection type optical coupling device according to a third embodiment, and FIG. 8 is a perspective view of a printed circuit board. This embodiment is the second
In the embodiment, the material of the printed circuit board 11 and the package 3
This is considered as a countermeasure when the material No. 1 and the material No. 1 have poor adhesiveness to each other.

The mounting pattern 1 is formed at a position where the resin molded on the printed circuit board 11 contacts the printed circuit board 11.
Through holes 11a are formed in a part of the printed circuit board 11 while leaving the patterns 2a and 12b and the connection patterns 13a and 13b, and when forming the package 31, the resin is wrapped around the through holes 11a to form the pattern. By doing so, the bonding strength between the printed circuit board 11 and the package 31 is increased. Since other configurations are the same as those of the first embodiment, corresponding or corresponding portions will be denoted by the same reference numerals and description thereof will be omitted.

[0024]

As described above, according to the present invention, since the electrode pattern is formed on the lower surface of the printed circuit board through the through hole without using the lead frame, surface mounting is possible and The mounting area can be reduced. Further, the bending process and the cutting process of the lead frame are unnecessary, and the cost can be reduced accordingly.

Furthermore, the wall thickness of the lower side of the mounting recess can be made sufficiently thin, and in combination with the above-mentioned reduction of the mounting area, a significant reduction in size can be achieved.

[Brief description of drawings]

FIG. 1 is a perspective view of a reflective optical coupling device according to a first embodiment of the present invention during an assembling stage.

FIG. 2 is a cross-sectional view showing a structure after assembly of the reflective optical coupling device in the first embodiment.

FIG. 3 is a perspective view of the reflective optical coupling device according to the application example of the first embodiment in the middle of assembly.

FIG. 4 is a cross-sectional view showing a structure after assembly of a reflective optical coupling device according to an application example of the first embodiment.

FIG. 5 is a sectional view showing the structure of a reflective optical coupling device in a second embodiment according to the present invention.

FIG. 6 is a perspective view of a reflective optical coupling device according to a second embodiment.

FIG. 7 is a sectional view showing the structure of a reflective optical coupling device in a third embodiment according to the present invention.

FIG. 8 is a perspective view showing a printed circuit board in the reflection type optical coupling device in the third embodiment.

FIG. 9 is a perspective view showing a structure of a conventional general reflection type optical coupling device.

FIG. 10 is a cross-sectional view showing the structure of a conventional general reflection type optical coupling device.

FIG. 11 is a cross-sectional view showing the structure of a conventional planar mounting type reflective optical coupling device.

FIG. 12 is a front view showing the structure of a conventional reflection type optical coupling device of a folded lead frame type.

[Explanation of symbols]

 11 printed circuit board 11a through hole 12a light emitting side mounting pattern 12b light receiving side mounting pattern 13a light emitting side wiring pattern 13b light receiving side wiring pattern 14a light emitting side electrode pattern 14b light receiving side electrode pattern 15a light emission Side electrode pattern 15b Light receiving side electrode pattern 16 Through hole 17 Recess forming substrate 17a Light emitting side through hole 17b Light receiving side through hole 17c Partition wall 18a Light emitting side mounting recess 18b Light receiving side mounting Recess 19 Light emitting element 20 Gold wire 21 Light receiving element 22 Gold wire 23a Light emitting side transparent sealing resin 23b Light receiving side transparent sealing resin 31 Package 31a Light emitting side mounting recess 31b Light receiving side mounting Recess 31c Partition wall 31d Fitting resin part

Claims (2)

[Claims] 1. A reflection type optical coupling device in which a light emitting element and a light receiving element are arranged side by side on a printed circuit board so as to be optically coupled to each other, wherein a mounting pattern on the light emitting side, a connection pattern and a light receiving circuit are provided on the upper surface of the printed circuit board. Side mounting patterns and connection patterns are formed, and electrode patterns are formed on the lower surface corresponding to the mounting patterns and connection patterns, respectively, and the mounting patterns and electrode patterns are formed through the through holes. Are electrically connected to each other and the wiring patterns and the electrode patterns are electrically connected through the through holes, and the mounting pattern and the wiring pattern on the light emitting side are separated by a partition wall. Each of the light-shielding recess forming substrates having a through hole corresponding to the above and a through hole corresponding to the light receiving side mounting pattern and connection pattern. Reflective optical coupling device, wherein a through hole is formed by integrally superposed on the printed circuit board so as to form a mounting recess of the respective light emitting and receiving side. 2. A reflection type optical coupling device in which a light emitting element and a light receiving element are juxtaposed on a printed circuit board so as to be optically coupled to each other, wherein a mounting pattern on the light emitting side, a connection pattern and a light receiving circuit are provided on the upper surface of the printed circuit board. Side mounting patterns and connection patterns are formed, and electrode patterns are formed on the lower surface corresponding to the mounting patterns and connection patterns, respectively, and the mounting patterns and electrode patterns are formed through the through holes. Is electrically connected to each other and each wiring pattern and each electrode pattern are electrically connected through a through hole, and the light-emitting side is formed by molding a light-shielding resin on the printed board. Mounting recess corresponding to the mounting pattern and the wiring pattern of the, and a mask corresponding to the mounting pattern and the wiring pattern of the light receiving side. Reflective optical coupling device package between the mounting recesses and a cement for the recess is separated by a partition wall, characterized in that are integral to the printed circuit board.