JPH05251734A - Optically coupled device - Google Patents

Abstract

PURPOSE:To improve electric insulation between a light-emitting element and a light-receiving element, and simplify the production process by providing an optically coupled device with two light-shading bodies which are separately formed for the light-emitting element and the light-receiving element. CONSTITUTION:A light-emitting element 13 and a light-receiving element 15 are injection molded separately, and then two shading bodies 18 and 19 are formed. The external area of the two shading bodies are integrally molded by use of coating resin 20 so that these elements 13 and 15 can be optically coupled. As a result, a light path chamber 21 can be formed in the two shading bodies 18 and 19. Therefore, a long light part can be made, and in addition, high insulating resistances of the two shading bodies and coating resin 20 are set, enough insulation between the light-emitting element and the light-receiving element can be ensured. By forming both light-shading substances 18 and 19 and the coating resin 20 of the same resin material, part of the surfaces of these light-shading bodies is molten at the time of injecting the coating resin 20. As a result, resin interface of the primary molded body and the secondary molded body can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of an optical coupling device (photocoupler).

[0002]

2. Description of the Related Art FIG. 6 shows the structure of a conventional double transfer mold type optical coupling device (photocoupler). In a conventional optical coupling device, a light emitting element 1 (LED) and a light receiving element 2 (phototransistor) are connected by 42 alloy or C
After being fixed to lead frames 3 and 4 made of u or the like with Ag paste (not shown) or the like, and electrically connecting the light emitting and receiving elements 1 and 2 and the lead frames 3 and 4 using a gold wire 5 or the like The mainstream type is a type that is covered with a transparent resin 6 such as silicon and is further molded with a light-shielding resin 7 mainly made of epoxy resin (conventional example 1). 7 is a process flow chart showing the manufacturing process of the optical coupling device shown in FIG.

[0003]

Generally, an optical coupling device is
It is like a relay used in a power supply section, etc., and requires a withstand voltage between the primary (light emitting side) and the secondary (light receiving side). Therefore, it is preferable that the distance between the light emitting side and the light receiving side is as long as possible.

However, in the case of the conventional example 1, since the positioning accuracy of the lead frames 3 and 4 is limited, in order to secure the optical coupling, the distance between the light emitting element 1 and the light receiving element 2 is shortened to some extent. Therefore, the insulation resistance is limited.

In order to solve such a problem, there has been an optical coupling device in which a single element for receiving and emitting light is inserted into a preformed case and hermetically sealed. The structure is shown in FIGS. 8 and 9, and the process flow chart is shown in FIG. That is, the single device 1a on the light emitting side and the single device 2a on the light receiving side are inserted into the outer case 8 molded using polycarbonate or the like so that the light receiving and emitting surfaces face each other and have substantially the same optical axis. The molded inner case 9 is inserted and fixed with a fixing light-shielding resin 7 such as an epoxy resin (conventional example 2).

In this structure, since the distance between the light receiving and emitting elements 1 and 2 can be made longer than that of the double transfer mold type, a high insulating property can be obtained, but as shown in the process flow chart of FIG. However, since there are many processes such as single item processing and manual work, the number of production steps is increased, and as a result, the production cost per product is expensive.

In view of the above problems, it is an object of the present invention to provide an optical coupling device which can improve the electrical insulation between light receiving and emitting and can simplify the manufacturing process.

[0008]

As shown in FIGS. 1 and 2, the means for solving the problem according to the first aspect of the present invention is to form a light-shielding member on the light-emission side integrally formed with a light-emitting element 13 and a lead-frame 12 on the light-emission side. The light-receiving side light-shielding body 19 is integrally formed with the light-receiving element 15 and the light-receiving side lead frame 14 on which the light-receiving element 15 and the light-receiving element 15 are mounted.
Is provided with an optical path chamber 21 that forms an optical path from the light emitting element 13 to the light receiving element 15, and both the light shields 18 and 19 are such that the elements 13 and 15 are optically arranged on the same optical axis in the optical path chamber 21. It is arranged so as to be coupled, and is integrally molded with the exterior resin 20.

According to a second aspect of the present invention, the means for solving the problem is to provide both the light shields 18 and 19 and the exterior resin 20 according to the first aspect.
Indicates that the same resin material is used.

According to a third aspect of the present invention, the insulation resistance of the resin material according to the second aspect is 10 ¹² Ω or more at room temperature around + 25 ° C. and 10 ¹¹ Ω at high temperature around + 100 ° C. The above is set.

[0011]

In the means for solving the problems according to the first to third aspects, the light emitting element 13 and the light receiving element 15 are individually subjected to the injection molding to form the two light shields 18 and 19. Around both of these two light shields 18 and 19, both elements 1
The exterior resin 20 is integrally molded so that the optical fibers 3 and 15 are optically coupled. Then, since the optical path chamber 21 can be formed in each of the light shields 18 and 19, the optical path length can be increased, and moreover,
Since the insulation resistance of both the light shields 18 and 19 and the exterior resin 20 is set to be large, the insulation between the light receiving and emitting can be sufficiently secured.

Further, in claim 2, both light shields 18, 19 are provided.
By forming the exterior resin 20 with the same resin material, a part of the surface of both the light shields 18 and 19 is melted when the exterior resin 20 is injected, and the resin interface between the primary mold body and the secondary mold body is eliminated. You can

[0013]

1 is a sectional view of an optical coupling device showing an embodiment of the present invention, FIG. 2 is a process flow chart showing a method of manufacturing an optical coupling device, and FIG. 3 is a diagram showing a state in which elements are arranged to face each other. ,
FIG. 4 is a diagram showing a state in which each light shield is formed, and FIG. 5 is a diagram showing a state in which both light shields are positioned.

As shown in the figure, the optical coupling device (photocoupler) of this embodiment is mounted on the light emitting element 13 mounted on the light emitting side lead frame 12 and the light receiving side lead frame 14 in the optical coupling device body 11. The light receiving element 15 and the light receiving element 15 are arranged so as to be optically coupled to each other on the same optical axis.

Each of the light emitting element 13 and the light receiving element 15 is integrally molded together with the lead frames 12 and 14 by a translucent resin 16 to form a single device.

The optical coupling device main body 11 includes a light-emitting side light-shielding body 18 and a light-receiving side light-shielding body 19 which are individually formed for the light-emitting element 13 and the light-receiving element 15, and an exterior resin integrally molded around them. 20 and 20.

The both light shields 18 and 19 are made of, for example, heat of polyphenylene sulfide (PPS), polycarbonate (PC), polybutylene terephthalate (PBT), crystalline polymer, amorphous polymer or liquid crystal polymer. Injection molding is performed using one kind of a plastic resin or a mixture thereof. The reason why the thermoplastic resin is used here is that the resin molding temperature has a low characteristic, and therefore it is considered that the influence on each of the elements 13 and 15 is low. Further, as the thermoplastic resin, a resin having an insulation resistance of 10 ¹² Ω or more at room temperature around + 25 ° C. and 10 ¹¹ Ω or more at high temperature around + 100 ° C. is used. The electrical insulation between the light emitting lead frames 12 and 14 is secured. By doing so, it meets the predetermined standard (German Federal Republic: VDE standard 0884) and can meet the demand for standardization and mass production of products.

A round hole-shaped optical path chamber 21 is formed in each of the light shields 18 and 19 in order to form an optical path from the light emitting element 13 to the light receiving element 15. The optical path room 2
1 is sealed when the two light shields 18 and 19 are arranged opposite to each other, and the length thereof is long so that the light emitting element 13 and the light receiving element 15 are electrically insulated from each other.

The exterior resin 20 is made up of the light shields 18, 1
The same light-shielding material as that of No. 9 is used, and the entire periphery thereof is injection molded.

In FIG. 1, reference numeral 16a is a translucent lens for improving the light directivity.

The optical coupling device having the above structure is manufactured as in the flow chart of FIG. First, as shown in FIG. 3, the light emitting element 13 and the light receiving element 15 are molded with the translucent resin 16 and are arranged to face each other as a single device.

Next, as shown in FIG. 4, each of the light emitting element 13 and the light receiving element 15 is individually subjected to the injection molding with a thermoplastic resin to form the respective light shields 18 and 19. At this time, the optical path chamber 21 is formed long.

Then, as shown in FIG. 5, both the light shields 18 and 19 are opposed to each other so that the elements 13 and 15 are optically coupled on the same optical axis in the optical path chamber 21. As shown in FIG. 1, the periphery is integrally molded with the exterior resin 20.

The above work is simultaneously performed using a plurality of lead frames 12 and 14 connected in a multiple manner in a state where they are juxtaposed with respect to a plurality of devices. After that, the lead frames 12 and 14 are cut for each optical coupling device main body 11 to complete an individual optical coupling device, which is then subjected to a test process.

Here, since the optical path chamber 21 is formed to be long and a resin material having a high insulation resistance is used as the light shields 18 and 19 and the exterior resin 20, the distance between the light emitting element 13 and the light receiving element 15 is increased. It is possible to obtain high insulation.

Further, for example, in the conventional example 2 shown in FIG. 10, the outer case, the inner case, etc. are processed individually, whereas the type of the present invention, as shown in FIG. Since the process can be performed up to the stage of molding as it is, the work such as positioning is facilitated by the mold, and the number of steps is reduced. Therefore, manual work can be eliminated and an inexpensive product can be provided by automation. Moreover, by molding the exterior resin 20 with a mold, the outer dimension accuracy thereof can be improved as compared with the fitting type as in Conventional Example 2.

Further, when the two light shields 18 and 19 are arranged in contact with each other, a slight gap may be formed due to a molding error. However, since the periphery of these is integrally molded with the exterior resin 20, the light path chamber 21 is exposed. Ingress of ambient light can be prevented. Therefore, a highly reliable optical coupling device can be provided.

Moreover, since both the light shields 18 and 19 and the exterior resin 20 are made of the same resin material, when the exterior resin 20 is injected, a part of the surfaces of both the light shields 18 and 19 are melted and the primary resin is removed. The resin interface between the molded body and the secondary molded body can be eliminated. Therefore, it is possible to prevent resin destruction and the like due to thermal expansion or thermal contraction.

The present invention is not limited to the above embodiment, and it goes without saying that many modifications and changes can be made to the above embodiment within the scope of the present invention.

For example, if the shape of the opening on one side of the light shields 18, 19 is convex and the shape of the opening on the other side is concave, positioning for optical coupling is ensured and workability is improved. improves.

The optical path chamber 21 does not have to be cylindrical, but may be rectangular or the like.

[0032]

As is apparent from the above description, according to claim 1 of the present invention, the light-emitting element and the light-receiving element are composed of two separately formed light-shielding members, which are integrally molded with the exterior resin. Since they are fixed, optical coupling can be ensured even if the optical path between the light receiving and emitting is made long, and the electrical insulation between them is improved. Moreover, the exterior resin can prevent the entry of ambient light, and can prevent malfunctions and the like.

Further, since the work of inserting both elements into the outer case as in the conventional example 2 can be omitted, manual work can be eliminated and the manufacturing efficiency can be improved by automation.

According to claim 2 of the present invention, since both the light-receiving and light-shielding body and the exterior resin are made of the same resin material, a part of the surface of both the light-shielding body is melted at the time of injecting the exterior resin so that these primary molds The resin interface between the body and the secondary mold body can be eliminated. Therefore, it is possible to prevent resin destruction and the like due to thermal expansion or thermal contraction.

According to claim 3 of the present invention, since the insulation resistances of both the light shields and the exterior resin are set to be large, an excellent effect can be obtained if the insulation withstand voltage between light reception and emission can be increased to meet a predetermined standard. is there.

[Brief description of drawings]

FIG. 1 is a sectional view of an optical coupling device showing an embodiment of the present invention.

FIG. 2 is a process flow chart showing a method for manufacturing an optical coupling device.

FIG. 3 is a diagram showing a state where elements are arranged to face each other.

FIG. 4 is a diagram showing a state in which each light shield is formed.

FIG. 5 is a view showing a state in which both light shields are positioned.

FIG. 6 is a sectional view of an optical coupling device of Conventional Example 1.

FIG. 7 is a process flow chart showing a method for manufacturing an optical coupling device of Conventional Example 1.

FIG. 8 is a sectional view of an optical coupling device of Conventional Example 2 when an inner case is inserted.

FIG. 9 is a sectional view of an optical coupling device of Conventional Example 2 after completion.

FIG. 10 is a process flow chart showing a method for manufacturing an optical coupling device of Conventional Example 2.

[Explanation of symbols]

 11 Optical Coupling Device Main Body 12 Light-Emitting Side Lead Frame 13 Light-Emitting Element 14 Light-Receiving Side Lead Frame 15 Light-Receiving Element 18 Light-Emitting Side Light Shield 19 Light-Receiving Side Light Shield 20 Exterior Resin 21 Optical Path Chamber

Claims (3)

[Claims] 1. A light emitting side light shield integrally formed with a light emitting element and a light emitting side lead frame mounting the same, and a light receiving side light shield integrally formed with a light receiving element and a light receiving side lead frame mounting the same. An optical path chamber for forming an optical path from the light emitting element to the light receiving element is provided in each of the light shields, and both the light shields are optically coupled to each other on the same optical axis in the optical path chamber. The optical coupling device is characterized in that it is arranged in such a manner that it is integrally molded with an exterior resin. 2. The optical coupling device according to claim 1, wherein the both light shields and the exterior resin are made of the same resin material. 3. The insulation resistance of the resin material according to claim 2,
10 ¹² Ω or more at room temperature around + 25 ° C, and +10
An optical coupling device, which is set to 10 ¹¹ Ω or higher at a high temperature of around 0 ° C.