JP3401128B2 - Method for manufacturing multi-channel optical coupling device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multi-channel type optical coupling device in which a plurality of light emitting / receiving elements are integrated.

[0002]

2. Description of the Related Art There are roughly two types of conventional optical coupling devices. (1) As shown in FIG. 5, a transparent silicone resin 5 is provided between a light emitting element 3 and a light receiving element 4 mounted on lead frames 1 and 2. A structure in which it is sealed and the periphery thereof is transfer-molded with an opaque epoxy resin 6 for light shielding, (2) FIG.
As shown in FIG. 3, there is a structure in which the light emitting element 3 and the light receiving element 4 covered with the transparent silicone resin 5 are transfer-molded with a semitransparent epoxy resin 7, and further with an opaque epoxy resin 6 for light shielding.

As a method of manufacturing this optical coupling device,
In the case of (1), a light emitting element (GaAs light emitting diode, etc.)
3 and a light receiving element (Si phototransistor, etc.) 4 are respectively connected to metallic lead frames 1 and 2 by Ag paste, and the electrode portions of the respective elements 3 and 4 and the lead frames 1 and 2 are connected.
And are connected by an Au wire 8. Offset bending is performed on the lead frames 1 and 2 at the portions where the elements 3 and 4 are connected so that the light emitting element 3 and the light receiving element 4 are arranged to face each other. The light emitting side lead frame 1 and the light receiving side lead frame 2 are combined so that the optical axes of the elements are aligned with each other, and in this state, the transparent silicone resin 5 is injected into the space between both elements and cured to form the optical coupling portion 9. After that, the epoxy resin is sealed by transfer molding using a die, and then the external lead frame is processed to form a product as shown in FIG.

In the case of (2), as in the case of (1), when the light emitting side lead frame 1 and the light receiving side lead frame 2 are combined so that the optical axes of the elements are aligned, a semitransparent epoxy resin 7 is formed. Transfer molding is performed, and then transfer molding is performed using an opaque epoxy resin 6. The subsequent steps are the same as those in (1).

The above-mentioned optical coupling device is of a single channel type as shown in FIG. 7, but in a programmable controller having a plurality of input / output terminals, a plurality of input / output insulations are required. Such a multi-channel type optical coupling device is mounted.

As shown in FIG. 9, this optical coupling device manufacturing method includes a light emitting side lead frame 1 and a light receiving side lead frame 2 each having a plurality of lead terminals 10 corresponding to the light emitting element 3 and the light receiving element 4, respectively. , 4 are mounted, and the electrode portions of the respective elements 3, 4 and the lead terminals 10 are connected by the Au wires 8. Then, the light emitting side lead frame 1 and the light receiving side lead frame 2 are combined so that the optical axes of the elements are aligned with each other, and transfer molding is performed using a translucent epoxy resin 7 as shown in FIG. 10 to form an optical coupling portion 9. Then, epoxy resin sealing is performed by transfer molding using a die.

[0007]

By the way, with the miniaturization of the equipment, the high-density mounting on the substrate is advanced, and the components mounted on the substrate are also required to be miniaturized. Therefore, in the multi-channel optical coupling device, , Package size reduction, and lead pitch reduction are being demanded. FIG. 11 shows an optical coupling device that meets the demand for miniaturization. At present, there are products with a lead pitch of 1.27 mm.

In a multi-channel type optical coupling device, mutual interference between channels (hereinafter referred to as crosstalk).
Should be kept to a level at which there is no problem in operation. For example, it is necessary to have a structure in which there is no light leakage between channels that causes a malfunction of the light receiving element of two channels due to the light emission of the light emitting element of one channel.

In the structure of the optical coupling device of the above (1) and (2), the crosstalk between the channels is prevented by forming a wall between the adjacent optical coupling parts by the opaque epoxy resin for light shielding. However, as miniaturization of the optical coupling device progresses, the distance between each optical coupling part becomes narrower,
The following problems arise.

In (1), when the silicone resin is injected, the distance between the channels is too small, and the silicone resin is connected, so that the light shielding property between the channels cannot be maintained.

In (2), the light-shielding portion is formed by the upper and lower molds 12 and 13 at the time of performing transfer molding with the translucent epoxy resin shown in FIG.
The thickness A of the light-shielding portion between the channels is determined by the distance between the optical coupling portions, but about 200 μm is required in terms of the strength of the mold, and this restriction limits the miniaturization of the package.

In view of the above, it is an object of the present invention to manufacture a multi-channel type optical coupling device in which the distance between channels is narrowed while preventing crosstalk between adjacent channels.

[0013]

A means for solving the problems according to the present invention is to form a plurality of primary bodies in each of which a light emitting element and a light receiving element having one or two or more intervals are opposed to each other. A plurality of light-emitting elements and a plurality of light-receiving elements are opposed to each other and optically coupled by combining the bodies and molding with a light-shielding resin, and these are arrayed in a multiple array and integrated. A multi-channel type optical coupling device is manufactured.

Specifically, lead terminals for mounting the light emitting elements are formed on the light emitting side lead frame at intervals of one, and lead terminals for mounting the light receiving elements on the light receiving side lead frame at intervals of one. And two light-emitting elements are opposed to each other to form two sets of primary bodies in which optical coupling parts optically coupled by a transparent resin such as a transparent silicone resin or a transparent epoxy resin are arranged. A multi-channel optical coupling device is completed by stacking the lead frames so that the optical coupling portion of the other primary body is inserted between the optical coupling portions of the secondary body and performing secondary molding with a light shielding resin. To be done.

Therefore, when forming the optical coupling portions, a sufficient distance can be secured between the optical coupling portions, and the optical coupling portions can be arranged at a narrow pitch when completed. This has the advantage of being able to solve the problem of silicone resin contact between channels during the formation of the optical coupling part, and also having the advantage that the thickness of the light shielding part between the optical coupling parts of the transfer mold can be made sufficient. Can be narrowed.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 11, a multi-channel type optical coupling device of the present invention has a plurality of light emitting elements 3 and a plurality of light receiving elements 4 arranged to face each other, and is optically made by a transparent resin. It is a surface mount type having an optical coupling section 9 coupled to each other, a plurality of optical coupling sections 9 being electrically insulated, arranged in a line in multiple rows, and integrated by a light shielding resin.

As shown in FIG. 1, the light emitting element 3 is die-bonded to the mounting portion 23 of one lead terminal 21 of the pair of lead terminals 21 and 22 formed in the cradle 20 of the light emitting side lead frame 1A, and the other one. It is connected to the lead terminal 22 by the Au wire 8. The interval between the lead terminals 21 matches the interval between the light emitting elements 3 arranged in every other line of the optical coupling device, and is formed corresponding to the odd channels. Similarly, the light emitting side lead frame 1B corresponding to the even-numbered channels is also formed.

Similarly, for the light-receiving element 4, two types of light-receiving side lead frames 2A and 2B corresponding to odd-numbered channels and even-numbered channels are formed, and are mounted on the respective lead terminals 21 similarly to the light-emitting element 3. In the figure, 24 is a tie bar for connecting the lead terminals.

After the light emitting side lead frame 1A and the light receiving side lead frame 2A corresponding to the odd-numbered channels are positioned and fixed so as to face each other with their optical axes aligned, the light shielding portion between channels shown in FIG. The optical coupling portion 9 is transfer-molded with the semitransparent epoxy resin 7 using the molds 25 and 26. As a result, one primary body 27 is formed as shown in FIG. Further, the light emitting side lead frame 1B and the light receiving side lead frame 2B corresponding to the even-numbered channels are similarly molded to form another primary body 28.

After cutting the tie bars 24 connecting the lead terminals 21 and 22 adjacent to each other in the primary bodies 27 and 28, the optical coupling portions 9 of the two primary bodies 27 and 28 are alternately arranged. Position and combine them so that they are evenly spaced. That is, as shown in FIG. 4, the cradle 20 on both sides of each primary body 27, 28 is overlapped. Then, transfer molding is performed by using an opaque epoxy resin 6 for light shielding, the cradle 20 is removed, and then the lead terminals 21,
22 is formed to complete the multi-channel optical coupling device. When the primary bodies 27 and 28 are superposed, the heights of the lead terminals 21 and 22 are deviated, but the difference is slight, so there is no problem as a product.

In this way, the lead frame is separated so as to correspond to the even-numbered channel and the odd-numbered channel, and the primary body having a large distance of the optical coupling portion is formed in advance,
By combining the respective primary bodies so that the optical coupling portions are arranged at a narrow pitch, it is possible to secure a sufficient thickness between the optical coupling portions of the transfer mold molding die for forming the optical coupling portions. Therefore, the distance between the adjacent optical coupling portions can be minimized, and the lead pitch of the optical coupling device can be reduced from 2.54 mm to 1.27 mm and further to 0.8 mm. It is possible to achieve high density mounting, and it is possible to reduce the size of the optical coupling device. Moreover, even if the size of the optical coupling device is reduced, since a light shielding wall made of an opaque epoxy resin is reliably formed between the optical coupling portions, crosstalk between the channels is also prevented.

The above-mentioned manufacturing method includes the primary mold and the second mold.
Although the present invention is applied to the optical coupling device having a structure to be molded next, it is also applicable to an optical coupling device having a structure in which a space between a light emitting element and a light receiving element is sealed with a transparent silicone resin. That is, after the light emitting side lead frame and the light receiving side lead frame corresponding to the odd-numbered channels are arranged to face each other, a transparent silicone resin is injected between the light receiving and emitting elements and thermosetting is performed to form one primary body. It Also, by molding the light emitting side lead frame and the light receiving side lead frame corresponding to the even-numbered channel in the same manner,
Form the next body. The subsequent process is the same as the above method.

In this case, since there is a sufficient distance between the channels when the silicone resin is injected, the silicone resin does not come into contact with each other, and even when manufacturing an optical coupling device having a narrow lead pitch, the distance between the channels is increased. The light-shielding property can be secured, and the optical coupling device can be downsized.

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. Although the lead frames are formed so that the light emitting elements and the light receiving elements are arranged alternately, the lead frames may be formed so that they are arranged every two, and three sets of lead frames may be combined.

[0025]

As is apparent from the above description, according to the present invention, when forming the optical coupling portions, the distances between the optical coupling portions can be set sufficiently and the optical coupling portions can be arranged at a narrow pitch when completed. Since it is possible to manufacture the optical coupling device, it is possible to achieve high density mounting while preventing crosstalk between adjacent channels, and it is possible to achieve miniaturization of the optical coupling device. If the miniaturization of the multi-channel optical coupling device progresses in this way, it can also contribute to the miniaturization of equipment having a large number of inputs and outputs such as a programmable controller.

[Brief description of drawings]

FIG. 1 is a view showing a lead frame divided into an even channel and an odd channel of the present invention.

FIG. 2 is a structural diagram of a transfer mold molding die.

FIG. 3 is a diagram showing a lead frame when an optical coupling portion is formed of a semitransparent epoxy resin.

FIG. 4 is a view showing a case where lead frames are overlapped and molded.

FIG. 5 is a sectional view of an optical coupling device in which an optical coupling portion is formed of transparent silicone resin.

FIG. 6 is a sectional view of an optical coupling device in which an optical coupling portion is formed of a semitransparent epoxy resin.

7A and 7B show a single-channel optical coupling device, FIG. 7A is a plan view, FIG. 7B is an internal connection diagram, FIG. 7C is a front view, and FIG.

FIG. 8 shows a multi-channel type optical coupling device, (a) is a plan view, (b) is an internal connection diagram, (c) is a front view, and (d) is a side view.

FIG. 9 is a diagram showing a lead frame on which elements are mounted in a conventional method for manufacturing a multi-channel type optical coupling device.

FIG. 10 is a diagram showing a lead frame when an optical coupling portion is formed of a semitransparent epoxy resin.

FIG. 11 shows a multi-channel compact optical coupling device,
(A) is a plan view, (b) is an internal connection diagram, (c) is a front view, and (d) is a side view.

FIG. 12 is a structural diagram of a conventional mold for transfer molding.

[Explanation of symbols]

1A, 1B Light emitting side lead frame 2A, 2B Light receiving side lead frame 3 light emitting element 4 Light receiving element 5 Transparent silicone resin 6 Opaque epoxy resin 7 Semi-transparent epoxy resin 9 Optical coupling section 21 Lead terminal 27,28 Primary

Claims (2)

(57) [Claims] 1. A light emitting device comprising a plurality of light emitting devices and a plurality of light receiving devices mounted on different lead frames.
In a multi-channel type optical coupling device in which a light receiving element and a light receiving element are arranged to face each other and are optically coupled, and these optical coupling portions are arranged in a multiple manner and integrated with each other, at least one or more light beams are provided at intervals. A plurality of primary bodies with aligned coupling parts are formed, one for each
Make sure that the optical coupling parts of
A method for manufacturing an optical coupling device, characterized in that lead frames are superposed and molded with a light-shielding resin. 2. A plurality of light emitting elements and a plurality of light receiving elements are arranged to face each other and are optically coupled, and these optical coupling portions are arranged in a multiple manner and integrated. In a channel-type optical coupling device, lead terminals for mounting light emitting elements are formed at intervals on the light emitting side lead frame, and lead terminals for mounting light receiving elements at intervals on the light receiving side lead frame are formed. Two sets of primary bodies, which are formed by facing each light emitting / receiving element and molded with a translucent resin to form optical coupling portions, are formed , and between the optical coupling portions of one primary body.
A method for manufacturing an optical coupling device, characterized in that the lead frames of the other primary body are overlapped with each other so that the optical coupling portion of the other primary body is inserted, and secondary molding is performed using a light shielding resin.