JP2003179251A - Optical coupler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate characteristics deterioration and to improve yield by preventing the light receiving surface of a light receiving element from being exposed out of an optical path body. <P>SOLUTION: The optical coupler comprises an emitting lead frame 11, a light emitting element 12 mounted on a header 11a of the emitting lead frame 11, a receiving lead frame 13, and a light receiving element 14 mounted on a header 13a of the receiving lead frame 13. A protrusion 31 is formed along the peripheral face of the light receiving element 14, and the emitting element 12 and the receiving element 14 are opposed with a specified space and optically coupled through a light-permeable resin to form an optical path 15 which covers the receiving element 14 disposed inside the protrusion 31. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coupling device, and more particularly to improvement of the structure of a photo MOS relay.

[0002]

2. Description of the Related Art Recently, in an optical coupling device, a voltage drive type photo MOS relay of low power consumption has become mainstream.

The structure of such a photo-MOS relay is shown in FIG.
Through FIG. FIG. 13 is a plan view of a light receiving element of a conventional photo MOS relay, FIG. 14 is a plan view showing a chip mounting state of the photo MOS relay, FIG. 15 is a cross-sectional view of the photo MOS relay, and FIG. It is a cross-sectional view showing the state of. Referring to these drawings, the photoMOS relay includes a light emitting side lead frame 1, a light emitting element (hereinafter referred to as a "light emitting chip") 2 mounted on the light emitting side lead frame 1, and a light receiving side lead frame. 3, a light receiving element (hereinafter, referred to as a “light receiving chip”) 4 mounted on the light receiving side lead frame 3,
Two output side lead frames 5 arranged with the light receiving side lead frame 3 interposed therebetween, and each output side lead frame 5
And a light-emitting chip 2 and a light-receiving chip 4 are arranged so as to face each other at a predetermined distance so as to be on substantially the same optical axis. And is optically coupled by a resin to form an optical path body (hereinafter referred to as “optical path”) 7.

This type of photo-MOS relay is manufactured as follows. That is, first, the light emitting chip 2 and the light receiving chip 4 are individually provided to the light emitting side lead frame 1 and the light receiving side lead frame 3 made of metal such as copper, iron, and 42 alloy, which are bent in consideration of facing each other in advance. Then, it is die-bonded with a conductive paste such as a silver paste. In parallel with this, a MOS chip 6 for switching is similarly bonded to the output side lead frame 5 with a conductive paste and die-bonded. next,
Wire bonding is performed on the outer lead portions of the lead frames 1, 3, 5 by using a bonding wire such as a gold wire. Then, by spot welding or by setting it on a loading frame or the like, the light emitting chip 2 and the light receiving chip 4 are arranged so as to face each other at a predetermined interval so as to be substantially on the same optical axis, and are optically filled by filling resin. An optical path 7 between the light emitting chip 2 and the light receiving chip 4 is formed by combining them. For this resin, it is common to use a translucent silicone resin for the purpose of stress relaxation such as junctions of the light emitting chip 2 and the light receiving chip 4. Then, after the optical path 7 is formed, transfer molding is performed using a light-shielding epoxy resin to form the exterior body 10, and the photo MOS relay is completed.

[0005]

In the photo MOS relay, however, as shown in FIG. 13, the control circuit 8 of the MOS chip 6 and the plurality of light receiving cells 9 are formed on the light receiving surface of the light receiving chip 4. The electromotive voltage and the current are regulated by the area and the number of the light receiving cells 9.

However, in the conventional photo-MOS relay, the silicon resin is filled to form the optical path 7, but at this time, the optical path 7 is deformed due to a change in the viscosity of the silicon resin, a difference in the injection angle and the like. To do. Therefore, FIG.
As shown in, there is a case where the silicon resin is not applied to a part of the light receiving chip 4 due to the non-filling of the resin. In this case, in the photo MOS relay, the voltage and current are determined by the area and number of the light receiving cells 9, so that part or all of the light receiving cells 9 on the light receiving surface of the light receiving chip 4 are out of the range of the optical path 7.
There will be insufficient electromotive force and insufficient current. As a result, the electrical characteristics of the finished product will be poor, and in the process of forming the optical path 7, it will be necessary to increase the incidental cost control by subtle device adjustment and strict silicon resin management, and to perform advanced optical path inspection. This is a factor of high cost due to a decrease in yield.

In view of the above problems, it is an object of the present invention to provide a low cost optical coupling device by improving the yield.

[0008]

A light emitting side lead frame, a light emitting element mounted on a header portion of the light emitting side lead frame, a light receiving side lead frame, and the light receiving side lead are provided. An optical coupling device comprising a light receiving element mounted on a header portion of a frame, and an optical path body formed of translucent resin filled between the light emitting element and the light receiving element, which are arranged to face each other, A projection is formed along the outer peripheral surface of, and the light receiving element disposed inside the projection is covered with the optical path body.

In the above structure, since the projection is formed along the side surface of the light receiving element, the light transmitting resin is prevented from flowing out when the optical path body is formed, and the light receiving surface of the light receiving element is transmitted. As a result of being easily covered with the transparent resin, a part of the light-receiving surface of the light-receiving element does not protrude from the transparent resin.

Therefore, the yield defect in the inspection process can be reduced, and the incidental work in the process can be light. As a result, it is possible to significantly reduce the cost.

Further, the distance between the primary and the secondary (the distance between the light emitting side wire loop top and the surface of the light receiving element) becomes long,
The header portion of the light emitting side lead frame and the header portion of the light receiving side lead frame can be brought close to each other. As a result, the optical coupling device can be downsized.

The protrusion is formed by bending the side surface of the header portion of the light receiving side lead frame toward the light receiving element.

In the above structure, since the projection is formed by bending the side surface of the header portion of the light-receiving side lead frame toward the light-receiving element side, the flow of the light-transmitting resin can be prevented without using a special method when forming the optical path body. You can get dam effect to prevent.

The protrusions are made of a resin having high viscosity and low fluidity.

In the above structure, since the protrusion is formed of a resin having high viscosity and low fluidity, the header portion of the lead frame on the light receiving side is not specially processed in advance, and the protrusion is formed when the optical path body is formed. It is possible to obtain a dam effect that prevents the flow of the light-sensitive resin.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a sectional view of a photo MOS relay according to a first embodiment of the present invention before exterior molding, and FIG. 2 is a plan view of the same photo MOS relay before exterior molding. . With reference to these drawings, the photoMOS relay according to the present embodiment is provided with a light emitting side lead frame 11
And the header portion 11a of the light emitting side lead frame 11
A light emitting element (hereinafter referred to as "light emitting chip") 12 mounted on the light receiving side lead frame 13, a light receiving element mounted on a header portion 13a of the light receiving side lead frame 13 (hereinafter referred to as "light receiving chip"). 14),
Two output side lead frames (not shown) arranged with the light receiving side lead frame 13 sandwiched therebetween, and a MOS element (not shown) mounted on the header portion of each output side lead frame (hereinafter, referred to as “MOS chip”). The light emitting chip 12 and the light receiving chip 14 are arranged so as to face each other at a predetermined distance so as to be substantially on the same optical axis by a light-transmitting resin, for example, a silicon resin having a light-transmitting property. An optical path body (hereinafter referred to as “optical path”) 15 is formed by being optically coupled.

The light emitting side lead frame 11 and the light receiving side lead frame 13 are made of metal such as copper, iron and 42 alloy, and are bent in consideration of facing each other in advance. The header part 13a of the lead frame 13 on the light receiving side has a recess 1 formed by stamping with a mold or the like.
6 is formed. The area and depth of this recess 16 are
It is set so that the entire light receiving chip 14 enters.
For example, the depth is 0.1 to 0.5 mm. Further, the peripheral wall 16a of the recess 16 is inclined so as to descend from the outside toward the inside. The peripheral wall 16a is inclined because
This is because a taper is formed on the mold during stamping to improve the mold release of the work, that is, the lead frame 13 on the light receiving side, and the silicon resin easily flows into the recess 16. The peripheral wall 16a may be vertically ground by a milling machine or the like.

As the light emitting chip 12, for example, a light emitting diode or the like is adopted, while as the light receiving chip 14, a photodiode, a phototransistor or the like is adopted. A MOS is formed on the light receiving surface of the light receiving chip 14.
A control circuit (not shown) of the chip and a plurality of light receiving cells (not shown) are formed, and the electromotive voltage and current of the photo MOS relay are defined by the area and number of the light receiving cells. There is.

FIG. 3 is a flow chart showing a method for manufacturing a photo MOS relay. Referring to the figure, the light emitting chip 12 is mounted on the header portion 11 a of the light emitting side lead frame 11.
Is bonded by a conductive paste such as silver paste and die-bonded, and the light-receiving chip 14 is bonded in the recess 16 formed in the header portion 13a of the light-receiving side lead frame 13 using the same means as the light-emitting chip 12. Die bond. In parallel with this, a MOS chip for switching is similarly bonded to the output side lead frame with conductive paste and die-bonded.

Then, wire bonding is performed by connecting to the outer lead portions of the light emitting side lead frame 11, the light receiving side lead frame 12 and the output side lead frame with a bonding wire such as a gold wire.

Next, the light emitting chip 12 is subjected to spot welding, setting on a loading frame, or the like.
Then, the light emitting chip 12 and the light receiving chip 14 are arranged so as to face each other with a predetermined gap so that the light receiving chip 14 is substantially on the same optical axis, and then a silicon resin having a light transmitting property is filled (injected) and light is emitted. The path 15 is formed to optically couple the light emitting chip 12 and the light receiving chip 14. At this time, if the lead frames 11 and 13 or the silicon resin coating portion are held obliquely, the filling (injection) of the silicon resin becomes easy. Alternatively, the light emitting side and the light receiving side may be separately coated with silicon resin, and then the light emitting chip 12 and the light receiving chip 14 may be arranged to face each other with a predetermined gap.

Thereafter, exterior molding is performed by transfer molding using a light-shielding epoxy resin, exterior plating is performed, and tie bars and lead cuts are performed, whereby the photo-MOS relay is completed.

In this embodiment, a recess 16 larger than the light-receiving chip 14 is formed in the header portion 13a of the light-receiving side lead frame 13, the light-receiving chip 14 is mounted in the recess 16, and the entire light-receiving chip 14 is covered by the optical path 15. Therefore, even if the light receiving surface of the light receiving chip 14 and the surface of the header portion 13a of the light receiving side lead frame 13 are substantially flush with each other and the light receiving cells are arranged up to the vicinity of the edge of the light receiving chip 14, the The light receiving cell does not overflow.

Therefore, the light does not enter a part of the light-receiving chip 14 and the characteristic does not become defective, the yield defect in the inspection process can be reduced, and the incidental work in the process can be light. As a result, it is possible to significantly reduce the cost.

Further, since the distance between the primary and the secondary (the distance between the wire loop top on the light emitting side and the surface of the light receiving chip 14) becomes long, the header portion 11 of the lead frame 11 on the light emitting side is increased.
It is possible to bring a and the header portion 13a of the light-receiving side lead frame 13 close to each other. As a result, the photo MOS relay can be downsized.

(Second Embodiment) FIG. 4 is a sectional view of a photo MOS relay according to a second embodiment of the present invention before exterior molding, and FIG. 5 is a plan view of the photo MOS relay before exterior molding. Is. Referring to these drawings, the photo MOS relay of the present embodiment is characterized in that the header portion 11a of the light emitting side lead frame 11 on which the light emitting chip 12 is mounted is trimmed to remove the header of the light emitting side lead frame 11. The dimension y of the portion 11a is sufficiently small to be 0.2 to 0.6 times the dimension x of the header portion 13a of the light-receiving side lead frame 13, and other configurations are substantially the same as those of the first embodiment. is there. Here, the blank portion is a portion outside the surface contact with the light emitting chip 12 when the light emitting chip 12 is mounted, and is a portion that does not hinder the mounting of the light emitting chip 12.

In the present embodiment, the dimension y of the header portion 11a of the light emitting side lead frame 11 is sufficiently smaller than the dimension x of the header portion 13a of the light receiving side lead frame 13 by 0.2 to 0.6 times. Therefore, the silicon resin swells outward due to surface tension between the light emitting side lead frame 11 and the light receiving side lead frame 13, and the cross-sectional shape of the optical path 15 becomes a dome shape, which is sufficiently wider than the light emitting side. The curvature of the applied silicone resin can be fully utilized.

Therefore, the thickness of the silicon resin on the periphery of the light-receiving side lead frame 13 does not become thin, and the uncoated portion of the silicon resin due to surface tension or the like can be reduced, and as a result, the yield can be improved. it can. Further, by forming the optical path 15 into a dome shape, it is possible to increase the incident light on the light receiving surface by reflection, refraction, and diffraction phenomena, absorb the variation in the performance of the light receiving cells of the light receiving chip 14, and receive the light receiving chip 14 The performance of can be improved.

By the way, if the dimension y of the header portion 11a of the light emitting side lead frame 11 is smaller than 0.2 times the dimension x of the header portion 13a of the light receiving side lead frame 13,
When the silicon resin is injected, the silicon resin spreads in the lateral direction and the header portion 11a of the light emitting side lead frame 11
Therefore, the light emitting chip 12 cannot be sufficiently covered. Header part 11a of the lead frame 11 on the light emitting side
Is the header portion 13 of the lead frame 13 on the light receiving side.
If the dimension x of a is larger than 0.6 times, the constriction in the middle of the optical path 15 becomes large and the light receiving chip 14 is exposed from the optical path 15 when the injection amount of the silicon resin is small.
A large amount of silicone resin must be injected. Therefore, the dimension y of the header portion 11 a of the light emitting side lead frame 11 is equal to the dimension y of the header portion 13 of the light receiving side lead frame 13.
0.2 times to 0.6 times the dimension x of a is suitable.

Although the light-receiving side lead frame 13 is formed with the recess 16 in which the light-receiving chip 14 is mounted, as shown in FIG. 6, the above effect can be obtained without the recess.

(Third Embodiment) FIG. 7 is a sectional view of a photo MOS relay according to a third embodiment of the present invention before exterior molding, and FIG. 8 is a plan view of the same photo MOS relay before exterior molding. . Referring to these drawings, the feature of this embodiment is that the header portion 1 of the light emitting side lead frame 11 is
The side surface of 1a (3 directions excluding the lead portion) is the light emitting chip 1
By bending the side surface (three directions except the lead portion) of the header portion 13a of the light-receiving side lead frame 13 toward the light-receiving chip 14 side while bending to the 2 side, the protrusions 30 and 31 are formed on both header portions 11a and 13a. The point is that the flow of the silicone resin is blocked, and other configurations are similar to those of the first embodiment. In addition, each protrusion 3
The heights A and B of 0 and 31 are 0.15 to 0.5 mm, and may be at least the height of the light receiving chip 14.

In this embodiment, each lead frame 1
By bending the side surfaces of the header parts 11a and 13a of Nos. 1 and 13 toward the chips 12 and 14, respectively, protrusions 30 and 31 are formed on both header parts 11a and 13a, and the flow of the silicone resin is blocked so that the light is blocked. Since the silicon resin is prevented from flowing out when the path 15 is formed, the light receiving surface of the light receiving chip 14 can be easily covered with the silicon resin. As a result, the same operational effect as the first embodiment is obtained.

Further, since the side surface of the header portion 13a of the light-receiving side lead frame 13 is bent toward the light-receiving chip 14 side, the projection can be formed without using a special method when forming the optical path 15, and the silicon can be formed. A dam effect that prevents the flow of resin can be obtained.

Further, the header portions 11a and 13 of the lead frames 11 and 13 bent toward the chips 12 and 14 respectively.
When a is made to face each other, the shape of the facing portion has a structure in which the cups face each other. Therefore, the optical path 15
The shape after application of the silicone resin when forming is stable in the shape as shown in FIG. As a result, it is possible to prevent the light receiving cells on the light receiving surface of the light receiving chip 14 from being exposed.

(Fourth Embodiment) FIG. 9 is a sectional view of a photo MOS relay according to a fourth embodiment of the present invention before exterior molding, and FIG. 10 is a plan view of the photo MOS relay before exterior molding. . With reference to these drawings, the feature of this embodiment is that a protrusion 32 is formed using a resin having high viscosity and low fluidity so as to surround the periphery along the side surface of the light receiving chip 14, The point is that the flow is blocked, and other configurations are the same as in the first embodiment.

FIG. 11 is a flow chart showing a method for manufacturing a photo MOS relay. Referring to the figure, the optical path 1
When forming 5, the light receiving side lead frame 13
Light-receiving chip 14 die-bonded to the header portion 13a of the
A high-viscosity and low-fluidity silicone resin is applied around the to form the protrusion 32. The height C of the protrusion 32 is preferably equal to or higher than the height of the light receiving chip 14, and is, for example, 0.15 to 0.5 mm. After that, the region inside the protrusion 32 is filled with a low-viscosity silicone resin to form the optical path 15.

Since the steps up to forming the optical path 15 and the steps after forming the optical path 15 are the same as those in the first embodiment, the description thereof will be omitted.

In this embodiment, the protrusion 3 is formed along the side surface of the light receiving chip 14 by using a resin having high viscosity and low fluidity.
2 is formed so as to block the flow of the silicone resin, a dam effect for preventing the flow of the silicone resin can be obtained, and the header of the light-receiving side lead frame 13 is preliminarily provided as in the fourth embodiment. It is possible to obtain the dam effect of preventing the flow of the silicone resin when the optical path 15 is formed, without performing any special processing on the portion 13a.

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,
As shown in FIG. 12, an opening 40 may be formed in the light receiving side lead frame 13, and the light receiving chip 14 may be attached to the lower side of the light receiving side lead frame 13 so that the light receiving surface faces upward. The opening 40 is formed to be wider than the light receiving surface of the light receiving chip 14 and smaller than the light receiving chip 14,
2 does not block the optical path between the light receiving chip 14 and the light receiving chip 14. Therefore,
This means that the protrusion is directly formed on the light receiving chip 14,
The dam wall effect can be obtained by the peripheral wall of the opening 40, the area of the header portion 13a of the light-receiving side lead frame 13 to be coated with the silicone resin can be reduced, and the header portion 13a can be reduced to downsize the optical coupling device. it can.

Furthermore, in the third and fourth embodiments,
A recess 16 larger than the light receiving chip 14 may be formed in the header portion 13a of the light receiving side lead frame 13.

In the third and fourth embodiments, the size of the header portion 11a of the light emitting side lead frame 11 is 0.2 to 0.6 times the size of the header portion 13a of the light receiving side lead frame 13. You may make it small.

Furthermore, in the first to fourth embodiments, a thin glass plate may be arranged in a direction traversing the optical path 15 to cover the light receiving surface of the light receiving chip 14 with the thin glass plate.

In addition, in the first and second embodiments, the side surface of the header portion 11a of the light emitting side lead frame 11 is bent toward the light emitting chip 12 side, and the side surface of the header portion 13a of the light receiving side lead frame 13 is moved to the light receiving chip 14 side. The protrusions 30 and 31 may be formed by bending them to the side to block the flow of the silicone resin.

Furthermore, in the first and second embodiments,
The protrusion 32 may be formed along the side surface of the light receiving chip 14 using a resin having high viscosity and low fluidity so as to block the flow of the silicone resin.

Furthermore, in each of the above embodiments,
Although an example in which the present invention is applied to a photo MOS relay has been described, the present invention may be applied to an optical coupling device such as a photo coupler and a photo interrupter.

[0047]

As is apparent from the above description, according to the present invention, the projections for blocking the flow of the light-transmissive resin are formed along the side surface of the light-receiving element. As a result of preventing the resin from flowing out to the outside and easily covering the light receiving surface of the light receiving element with the light transmitting resin, a part of the light receiving surface of the light receiving element does not protrude from the light transmitting resin, The yield defect in the inspection process can be reduced, and the incidental work in the process can be negligible. As a result, it is possible to significantly reduce the cost.

Further, the distance between the primary and the secondary (the distance between the light emitting side wire loop top and the surface of the light receiving element) becomes long,
Since the header portion of the light emitting side lead frame and the header portion of the light receiving side lead frame can be brought close to each other, the optical coupling device can be downsized.

Since the projection is formed by bending the side surface of the header portion of the light receiving side lead frame toward the light receiving element side,
It is possible to obtain the dam effect of preventing the flow of the transparent resin without using a special method when forming the optical path body.

Further, since the projections are formed of a resin having high viscosity and low fluidity, the header portion of the lead frame on the light receiving side is not required to be specially processed in advance, and the translucent property is obtained when the optical path body is formed. A dam effect that prevents the flow of resin can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a photo MOS relay according to a first embodiment of the present invention before exterior molding.

FIG. 2 is a plan view of the photo MOS relay before exterior molding.

FIG. 3 is a flowchart showing a method for manufacturing a photo MOS relay.

FIG. 4 is a cross-sectional view of a photo MOS relay according to a second embodiment of the present invention before exterior molding.

FIG. 5 is a plan view of the photo MOS relay before it is externally molded.

FIG. 6 is a cross-sectional view of a photo MOS relay according to another embodiment before exterior molding.

FIG. 7 is a cross-sectional view of a photo MOS relay according to a third embodiment of the present invention before exterior molding.

FIG. 8 is a plan view of the photo MOS relay before exterior molding.

FIG. 9 is a cross-sectional view of a photo MOS relay according to a fourth embodiment of the present invention before exterior molding.

FIG. 10 is a plan view of the photo MOS relay before the outer molding.

FIG. 11 is a flowchart showing a method for manufacturing a photo MOS relay.

FIG. 12 is a cross-sectional view of a photo MOS relay according to another embodiment before exterior molding.

FIG. 13 is a plan view of a light receiving element of a conventional photo MOS relay.

FIG. 14 is a plan view showing a chip mounting state of a photo MOS relay.

FIG. 15 is a sectional view of a photo MOS relay.

FIG. 16 is a cross-sectional view showing a state of the photo MOS relay before being externally molded.

[Explanation of symbols]

11 Light emitting side lead frame 11a header part 12 Light emitting element (light emitting chip) 13 Light receiving side lead frame 13a header part 14 Light receiving element (light receiving chip) 15 Optical path body (optical path) 16 dents 30, 31, 32 protrusions

Claims (3)

[Claims] 1. A light emitting side lead frame, a light emitting element mounted on a header portion of the light emitting side lead frame, a light receiving side lead frame, and a light receiving element mounted on a header portion of the light receiving side lead frame, facing each other. In an optical coupling device comprising an optical path body formed of a translucent resin filled between the arranged light emitting element and light receiving element, a projection is formed along the outer peripheral surface of the light receiving element, and the projection is formed. An optical coupling device, wherein the light receiving element arranged inside is covered with the optical path body. 2. The optical coupling device according to claim 1, wherein the protrusion is formed by bending a side surface of a header portion of the light receiving side lead frame toward the light receiving element side. 3. The optical coupling device according to claim 1, wherein the protrusion is formed of a resin having high viscosity and low fluidity.