JP3472411B2 - Photo MOS relay - Google Patents

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.
14 to FIG. 11 is a plan view of a light receiving element of a conventional photo MOS relay, FIG. 12 is a plan view showing a chip mounting state of the photo MOS relay, FIG. 13 is a 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. 11, 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 light-transmitting plate is disposed in a direction crossing the light-transmitting body, the light-transmitting body is slightly larger than the light-receiving element and smaller than the header portion of the light-receiving side lead frame, and the light-transmitting plate is disposed between the light-receiving side lead frame. The entire light receiving element is covered with the transparent resin.

Another means for solving the problem is that a light-transmitting plate is arranged in a direction crossing the optical path member, and the light-transmitting member has substantially the same area as that of the header portion of the light-receiving side lead frame. The entire light receiving element is covered with the translucent resin between the light receiving side lead frame.

In the above structure, the light-transmitting plate is arranged in the direction traversing the light-path member, and the entire light-receiving element is covered with the light-transmitting resin between the light-transmitting plate and the lead frame on the light-receiving side. At the time of formation, the translucent resin adheres between the light receiving surface of the light receiving element and the translucent plate.

Therefore, it is possible to prevent the light receiving surface of the light receiving element from being exposed from the transparent resin.

[0012]

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.
It is a top view before the exterior molding of an S relay. With reference to these drawings, the photoMOS relay according to the present embodiment includes a light emitting side lead frame 11 and the light emitting side lead frame 1.
1 mounted on the header portion 11a of the light emitting element (hereinafter,
It is called a "light emitting chip". ) 12, a light-receiving side lead frame 13, and a light-receiving element mounted on the header portion 13a of the light-receiving side lead frame 13 (hereinafter referred to as "light-receiving chip").
Say. ) 14 and two output side lead frames (not shown) arranged with the light receiving side lead frame 13 interposed therebetween.
And a MOS element (not shown; hereinafter referred to as “MOS chip”) mounted on the header portion of each output side lead frame, and the light emitting chip 12 and the light receiving chip 1 are provided.
4 and 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 coupled by a light-transmitting resin, for example, a silicon resin having a light-transmitting property, to form an optical path body (hereinafter, referred to as “optical path”). 15) is formed.

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 the light emitting side lead frame 11, the light receiving side lead frame 12, and the outer lead portions of the output side lead frame with a bonding wire such as a gold wire.

Then, the light emitting chip 12 is spot-welded or set on a loading frame.
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.

After that, exterior molding is performed by transfer molding using light-shielding epoxy resin, exterior plating is performed, and tie bars and lead cuts are performed to complete the photo MOS relay.

In the present 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, it is possible to prevent the light from entering a part of the light-receiving chip 14 and to cause the characteristic defect, and it is possible to reduce the yield defect in the inspection process and the incidental work in the process is light. As a result, it is possible to significantly reduce the cost.

Further, since the primary-secondary distance (the distance between the light emitting side wire loop top and the surface of the light receiving chip 14) becomes long, the header portion 11 of the light emitting side lead frame 11 is
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 same 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 is not thinned, 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, the above effect can be obtained without the recess as shown in FIG.

(Third Embodiment) FIG. 7 is a sectional view of a photo-MOS relay according to a third embodiment of the present invention before the outer mold, and FIG.
It is a top view before the exterior molding of an S relay. With reference to these figures, the feature of this embodiment is that a thin glass plate 20 is arranged in the middle of the light path 15 so as to cross the optical path 15, and the light receiving surface of the light receiving chip 14 is slightly larger than the light receiving chip 14. The other configuration is the same as that of the first embodiment.

FIG. 9 is a flowchart showing a method for manufacturing a photo MOS relay. Referring to the figure, the optical path 15
When forming, the silicon resin 15a is first applied so as to cover the light emitting chip 12. In addition, the light receiving chip 14
The silicon resin 15b is applied so as to cover the thin glass plate 20, the thin glass plate 20 is placed on the silicon resin 15b so as to completely cover the light receiving chip 14, and the thin glass plate 20 is pressed. At this time, a pressing force is uniformly applied so that the thin glass sheet 20 does not tilt. Here, it is preferable that the pressing force of the thin glass sheet 20 is about 2 to 10 times the weight of the thin glass sheet 20 so that the previously applied bonding wire is not deformed or broken. After that, before the silicone resin covering the light emitting chip 12 hardens, the light emitting chip 12
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 and the light receiving chip 14 are substantially on the same optical axis.
An optical path 15 is formed with 0.

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, since the thin glass plate 20 is arranged in the direction crossing the optical path 15 and the light receiving surface of the light receiving chip 14 is covered with the thin glass plate 20, the light receiving chip 14 receives light when the optical path 15 is formed. The silicon resin 15b comes into close contact between the surface and the thin glass plate 20.

Therefore, the silicon resin 15b bulges outward between the thin glass plate 20 and the light-receiving side lead frame 13 to completely cover the peripheral edge of the light-receiving side lead frame 13, and the light-receiving surface of the light-receiving chip 14 is made of silicon resin. 15
It is possible to prevent the exposure from b.

As shown in FIG. 10, the thin glass plate 2
The area of 0 corresponds to the header portion 13 of the lead frame 13 on the light receiving side.
When it is set to be approximately the same as a, it is not necessary to press the thin glass plate 20 into contact, and the above effect can be obtained.

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. In the third embodiment, the 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.

Further, in the third embodiment, the size of the header portion 11a of the light emitting side lead frame 11 is sufficiently reduced to 0.2 to 0.6 times the size of the header portion 13a of the light receiving side lead frame 13. May be.

Furthermore, in the third embodiment, an example in which the thin glass plate 20 is used has been described, but instead of the thin glass plate 20, a light-transmitting thin plate such as plastic may be used.

In the first to third 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, and the side surface of the header portion 13a of the light receiving side lead frame 13 is received. The protrusion may be formed by bending it to the side to block the flow of the silicone resin.

Further, in the first to third embodiments, a protrusion is 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. You may

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.

[0040]

As is apparent from the above description, according to the present invention, since the light transmitting plate is arranged in the direction traversing the light path member and the light receiving surface of the light receiving element is covered with the light transmitting plate, As a result of the transparent resin being in close contact between the light receiving surface of the light receiving element and the transparent plate during formation, it is possible to prevent the light receiving surface of the light receiving element from being exposed from the transparent resin.

[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 flowchart showing a method for manufacturing a photo MOS relay.

FIG. 10 is a sectional view of a photo MOS relay according to another embodiment before exterior molding.

FIG. 11 is a plan view of a light receiving element of a conventional photo MOS relay.

FIG. 12 is a plan view showing a chip mounting state of a photo MOS relay.

FIG. 13 is a sectional view of a photo MOS relay.

FIG. 14 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 20 thin glass

─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-5-206505 (JP, A) JP-A-52-94090 (JP, A) JP-A-1-128478 (JP, A) JP-A-55- 11385 (JP, A) JP 58-162080 (JP, A) JP 61-214585 (JP, A) JP 53-66191 (JP, A) JP 60-24080 (JP, A) JP-A-6-5905 (JP, A) JP-A-8-8457 (JP, A) Actually open 2-136343 (JP, U) Actually open 64-16649 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 31/12

Claims (3)

(57) [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 plurality of light emitting surfaces mounted on the header portion of the light receiving side lead frame . A photo-MOS relay comprising a light-receiving element having a light- receiving cell and an optical path body formed of a light-transmissive resin filled between the light-emitting element and the light-receiving element, which are arranged to face each other, The translucent plate is arranged so as not to incline in the direction traversing the optical path member, and the translucent member is slightly larger than the light receiving element and smaller than the header portion of the light receiving side lead frame, and the light transmissive plate and the light receiving plate are arranged. the translucent resin between the side lead frame, outside
A photo-MOS relay that bulges to cover the entire light-receiving element. 2. 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 plurality of light receiving surfaces mounted on the header portion of the light receiving side lead frame . A photo-MOS relay comprising a light-receiving element having a light- receiving cell and an optical path body formed of a light-transmissive resin filled between the light-emitting element and the light-receiving element, which are arranged to face each other, The translucent plate is arranged so as not to incline in the direction traversing the optical path member, and the translucent member has substantially the same area as the header portion of the light receiving side lead frame, and the light transmissive plate and the light receiving side lead frame are A photo-MOS relay characterized in that the entire light-receiving element is covered with the translucent resin between. 3. The header portion of the lead frame on the light receiving side,
3. The photo MOS relay according to claim 1, wherein a recess larger than the light receiving element is formed, and the light receiving element is mounted in the recess.