JP2002344006A - Optically coupled device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact optically coupled device whose heat radiating performance is superior. SOLUTION: This optically coupled device is constituted of a light-emitting element 1; a light-receiving element 2; a light-emitting side lead frame 3a formed with a light-emitting element mounting part 3c for mounting the light-emitting element 1; a light-receiving side lead frame 3b, formed with a light-receiving element mounting part 3d for mounting the light-receiving element 2; translucent resin 6 covering the light-emitting element 1 and the light-receiving element 2, and covering a part of the light-emitting side lead frame 3a and the light- receiving side lead frame 3b, which is formed with a hole 9 at a position, corresponding to at least one of the back face of the light-emitting element mounting part 3c and the back face of the light-receiving element mounting part 3d; and light-shielding resin 7 covering the outer periphery of the translucent resin 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for converting an electric signal into an optical signal by a light emitting element and converting the optical signal into an electric signal again by a light receiving element. And an optical coupling device that electrically insulates the optical coupling device.

[0002]

2. Description of the Related Art As a conventional optical coupling device, an optical coupling device using a Darlington output type phototransistor as a light receiving element will be described with reference to FIG.

FIG. 7 is a side sectional view showing a schematic configuration of an optical coupling device. In FIG. 7, reference numeral 1 denotes a light emitting element such as a light emitting diode for converting an electric signal to light, 2 denotes a light receiving element such as a Darlington output type phototransistor for converting light to an electric signal, and 3a denotes the light emitting element 1 at its tip. A light emitting side lead frame connected and mounted with a conductive adhesive such as a paste is shown. Reference numeral 3c denotes a light emitting element mounting portion at the tip of the light emitting side lead frame 3a. Reference numeral 3b denotes a light-receiving-side lead frame on which the light-receiving element 2 is connected to and mounted on a leading end portion thereof with a conductive adhesive such as Ag paste. Reference numeral 3d denotes a light-receiving-element mounting portion at the leading end of the light-receiving side lead frame 3b. 4 is a transparent silicone resin for pre-coating the light emitting element 1, 5 is a wire for wire bonding the light emitting element 1 and the light receiving element 2 to the light emitting side lead frame 3a and the light receiving side lead frame 3b, respectively, 6 is the light emitting element 1 and the light receiving element Primary mold resin (translucent resin) covering 2, 8
Is a secondary mold resin (light-shielding resin) that covers the outer periphery of the primary mold resin 6.

[0004] The primary molding resin 6 is used for each element 1,
About 70% to reduce the stress applied when it comes into close contact with 2.
(Weight ratio), and the secondary mold resin 8 also contains about 70% (weight ratio) of the filler and the colorant.

In such an optical coupling device, first, an externally input electric signal is applied to the lead frame 3a.
Is transmitted to the light emitting element 1 via the Then, the electric signal is converted into an optical signal by the light emitting element 1, and the optical signal is transmitted to the light receiving element 2 through the primary molding resin 6.
Next, the light signal is converted into an electric signal by the light receiving element 2 and transmitted to the outside via the light receiving side lead frame 3b.

[0006] Such an optical coupling device is mainly used for signal transmission, and is also used for connecting a telephone line in a modem or the like necessary for network connection of a personal computer.

[0007] In the former optical coupling device for signal transmission, a phototransistor type light receiving element is usually used in many cases. The latter optical coupling device for connecting a telephone line usually requires a light-receiving element having a high withstand voltage and a high output. For example, the above-described Darlington output phototransistor and MOS relay are used. In particular, for the output current, JATE (Telecommunications Terminal Equipment Examination Association) shows that a test is performed by passing a current of 120 mA to the secondary side (light receiving element), and an optical coupling device for telephone line connection is used. Since the current flowing through the light receiving element is larger than that of the optical coupling device for other uses, the amount of heat generated is larger.

In a conventional modem using such an optical coupling device for connecting a telephone line, in a desktop personal computer built-in type or a single modem, this optical coupling device is used.
Even if a relatively large general-purpose DIP (Dual In-line Package) 4-pin package is used as a package made of the next molding resin or the like, there is no problem in the component mounting area. However, PCMCIA (Personal Computer Memory Card)
(International Association) Card-type modems, thin notebook personal computers, and the like have a limited mounting area, and small surface-mount SMD (Surface Mount Device) packages have been used.

However, in recent years, further miniaturization of devices
Thinning has become important, and accordingly, high-density mounting of boards to be incorporated in the device has been progressing. For example, such high-density mounting is progressing in the above-mentioned notebook personal computers, DC-DC converters, small-sized programmable controllers, and the like, and the above-described optical coupling device mounted on the substrate is no exception. There is a demand for a reduction in thickness.

Therefore, as a package of the above-described optical coupling device for signal transmission, a half-pitch (1.27 mm pitch) type package having a smaller package size is becoming mainstream in addition to a small surface-mount type SMD package.

[0011]

However, the optical coupling device for connecting a telephone line such as a modem as used in the above-mentioned prior art usually requires a light-receiving element of high withstand voltage and high output type. is there. At this time, due to the limitation of the size of the light receiving element required to satisfy the electrical characteristics of the light receiving element and the problem of heat dissipation of the package, the product lineup of packages smaller than the small surface mount type SMD package is currently available. Does not exist.

Therefore, such a high-withstand-voltage, high-output optical coupling device is further downsized (for example, a half-pitch (1.27 m
m) type package), it is necessary to further reduce the size of the light-receiving element. However, if the size is made smaller than the current size, when a Darlington output type phototransistor is used for the light-receiving element, the collector characteristics will increase. -The emitter-to-emitter saturation voltage increases, and the amount of heat generated further increases.

To solve this problem, for example, a heat radiating plate may be attached to the package to enhance heat radiation. However, this increases the size of the package, making it unusable for small and thin devices.

Further, a special frame may be provided so as to be directly connected to the light receiving element which generates a large amount of heat, and the frame may be drawn out of the package and function as a heat radiating member to enhance heat radiation. However, this would expose part of the internal wiring of the optical coupling device to the outside,
The insulation performance may not be maintained, and the optical coupling device may be damaged due to external electric noise or the like.

[0015] In addition, if an attempt is made to reduce the size of the optical coupling device, heat dissipation of the light emitting element also becomes a problem.

The present invention has been made to solve the above-described problems, and has as its object to provide a small-sized optical coupling device having excellent heat dissipation.

[0017]

In order to solve the above-mentioned problems, the present invention provides a light emitting element, a light receiving element, a light emitting side lead frame provided with a light emitting element mounting portion for mounting the light emitting element, and a light receiving element. A light-receiving side lead frame provided with a light-receiving element mounting section for mounting the light-emitting element and a light-receiving element, and a back surface of the light-emitting element mounting section or a light-receiving element, A light-transmitting resin having a hole at a position corresponding to at least one surface of the back surface of the mounting portion, and a light-shielding resin covering an outer periphery of the light-transmitting resin. .

According to the present invention, heat generated from at least one of the light-emitting element and the light-receiving element is transmitted from the back surface of the light-emitting element mounting portion or the back surface of the light-receiving element mounting portion to the light-shielding resin filling the hole, and further to the outside. Since the heat is dissipated, the heat dissipating property of the entire optical coupling device can be further improved. Therefore, even if the size of the light-receiving element is reduced in order to reduce the size of the package made of the light-shielding resin and the amount of heat generation is increased, since the heat radiation is excellent, various problems such as malfunction due to the heat generation and damage to parts are caused. It is possible to provide an optical coupling device which is small in size and excellent in heat dissipation.

Further, a plurality of holes are provided in the translucent resin,
By increasing the contact area between the back surface of the light-emitting element mounting portion or the back surface of the light-receiving element mounting portion and the light-shielding resin filling the plurality of holes, the heat dissipation can be further improved.
This also increases the contact area between the light-transmitting resin and the light-shielding resin, so that the adhesion can be improved, the heat generated from each element can be easily transmitted, and the heat dissipation can be further improved. .

Further, the present invention is characterized in that, in the optical coupling device, a corner portion in contact with a side surface and a bottom surface of the hole is rounded.

Further, the present invention is characterized in that, in the optical coupling device, the shape of the hole is a tapered shape in which the width on the bottom surface side is narrow, and the width increases as the distance from the bottom surface increases. .

According to the present invention, in the step of filling the outer periphery of the light-transmitting resin with the light-shielding resin by using a molding die or the like and performing molding, the light-emitting element mounting corresponding to the side surfaces of the holes and the holes. Since the light-shielding resin can be sufficiently filled up to the corner of the back surface of the portion or at least one surface of the back surface of the light-receiving element mounting portion, it is possible to prevent air voids from being generated. Accordingly, it is possible to prevent the corner portion from being filled with the light-shielding resin, thereby preventing heat radiation from being reduced.

Further, the present invention is characterized in that in the optical coupling device, an insulating member is arranged in the hole.

According to the present invention, the heat generated by at least one of the light emitting element and the light receiving element is more insulative than the translucent resin in contact with the back surface of the light emitting element mounting portion or the back surface of the light receiving element mounting portion. Since the heat is transmitted to the transparent member and transmitted to the light-shielding resin without passing through the light-transmitting resin, the heat is radiated to the outside. Therefore, even if the size of the light-receiving element is reduced in order to reduce the size of the package made of the light-shielding resin and the amount of heat generation is increased, since the heat radiation is excellent, various problems such as malfunction due to the heat generation and damage to parts are caused. It is possible to provide an optical coupling device which is small in size and excellent in heat dissipation.

Further, the present invention is characterized in that, in the optical coupling device, a part of the insulating member is exposed on a surface of the light shielding resin.

According to the present invention, the heat generated by at least one of the light emitting element and the light receiving element has a higher heat dissipation property than the light transmitting resin in contact with the back surface of the light emitting element mounting portion or the back surface of the light receiving element mounting portion. Since the heat is transmitted to the transparent member and is directly radiated to the outside without passing through the light-transmitting resin and the light-shielding resin, the heat radiation of the entire optical coupling device can be further improved.

Further, the present invention provides the optical coupling device, wherein the opening area of the hole is larger than the area of the mounting surface which is one surface of the light emitting element and smaller than the area of the mounting surface which is one surface of the light receiving element. It is a feature.

According to the present invention, when the opening area of the hole is larger than the area of the mounting surface, which is one surface of the light receiving element, the step of molding the light-transmitting resin usually comprises the steps of:
Due to the difference in the coefficient of linear expansion between the translucent resin and the light-receiving lead frame in the cooling process after thermosetting, the light-receiving lead frame bends in the hole direction, and the light-receiving element is affected by the pressure of the bending. Because it may be broken by receiving it greatly,
By making the area of the hole smaller than the area of the mounting surface, which is one surface of the light receiving element, the influence of the bending of the light receiving side lead frame can be suppressed, and the light receiving element can be prevented from being damaged and has a sufficient heat radiation effect. It is possible to obtain.

On the other hand, the light-emitting element is smaller in size than the light-receiving element, is pre-coated with a transparent silicone resin or the like, and further has a recess (recess) formed in a part of the light-emitting side lead frame to mount the light-emitting element Since the light emitting element is mounted thereon, the influence of the pressure of the deflection of the light emitting side lead frame applied to the light emitting element is considerably reduced, and as a result, the opening of the hole at a position corresponding to the back surface of the light emitting element mounting part is reduced. The area can be larger than the area of the mounting surface, which is one surface of the light emitting element.

[0030]

Embodiments of the present invention will be described below with reference to the drawings. In the figure, the same reference numerals are given to the same components as those described in the above-mentioned conventional technology.

[Embodiment 1] As Embodiment 1 of the present invention, an optical coupling device using a Darlington output type phototransistor as a light receiving element will be described with reference to FIGS.

FIGS. 1 and 2 are side sectional views showing a schematic configuration of the optical coupling device. 1 and 2, reference numeral 1 denotes a light emitting element such as a light emitting diode that converts an electric signal into light, 2 denotes a light receiving element such as a Darlington output type phototransistor that converts light into an electric signal, and 3a denotes a light emitting element 1 at its tip. A
g is a light emitting side lead frame connected and mounted with a conductive adhesive such as g paste, and 3c is a light emitting element mounting portion at the tip of the light emitting side lead frame 3a. Reference numeral 3b denotes a light-receiving-side lead frame on which the light-receiving element 2 is connected to and mounted on a front end portion thereof with a conductive adhesive such as Ag paste.
Is a light receiving element mounting portion at the tip of the light receiving side lead frame 3b. 4 is a transparent silicone resin for pre-coating the light emitting element 1 and 5 is a light emitting side lead frame 3a and a light receiving side lead frame 3b for the light emitting element 1 and the light receiving element 2, respectively.
Is a primary molding resin (translucent resin) that covers the light emitting element 1 and the light receiving element 2, and a position corresponding to the back surface of the light emitting element mounting portion 3c of 9a, 9c; A hole is provided at a position corresponding to the back surface of the 9d light receiving element mounting portion 3d. Reference numeral 7 denotes a secondary mold resin (light-shielding resin) that covers the outer periphery of the primary mold resin 6.

The primary mold resin 6 contains about 70% (weight ratio) filler for stress relaxation.
The next mold resin 7 contains a substantial amount (for example, about 80 to 90% (weight ratio)) of a filler of silica (crystalline silica or fused silica obtained by subjecting the crystalline silica to a heat treatment or the like) in order to enhance heat dissipation. Use a light-shielding resin. In the prior art, the secondary mold resin contains about 70% (weight ratio) of a silica filler, and in order to increase the heat dissipation, it is sufficient to contain more silica. If this is the case, the strength of the cured resin will decrease, so in the present invention, a resin containing about 80 to 90% (by weight) silica is used.

In FIG. 1, in the step of filling and molding the outer periphery of the primary molding resin 6 with the secondary molding resin 7 using a molding die or the like, the light emitting element mounting portion exposed by the holes 9a and 9b. 3c, the back surface of the light receiving element mounting portion 3d is directly in contact with the secondary mold resin 7.

Usually, when the opening area of the hole 9b is larger than the area of the mounting surface, which is one surface of the light receiving element 2, 1
In the step of molding and forming the next mold resin 6, due to the difference in linear expansion coefficient between the primary mold resin 6 and the light receiving side lead frame 3b in the cooling step after thermosetting, the light receiving side lead frame 3b When bent in the direction of the hole 9b, the light receiving element 2 may be broken under the influence of the bending pressure. Therefore, the area of the hole 9b is designed to be smaller than the area of the mounting surface, which is one surface of the light receiving element 2.

Furthermore, it is preferable that the size of the inner periphery of the hole 9b is such that it does not protrude from the outer periphery of the mounting surface, which is one surface of the light receiving element 2, and fits inside.

On the other hand, the light emitting element 1 is smaller in size than the light receiving element, for example, 0.28 mm × 0.28 mm × 0.28 mm.
Further, the light-emitting side lead frame 3 is pre-coated with a transparent silicone resin 4 and further has a thickness of, for example, about 0.2 mm.
Since a concave portion (recess) is formed in a part of “a” and is mounted as the light emitting element mounting portion 3c, the influence of the pressure of the deflection of the light emitting side lead frame 3a applied to the light emitting element 1 is considerably reduced. The opening area of the hole 9a is
It is designed to be larger than the area of the mounting surface which is one surface of the light emitting element 1 and smaller than the area of the mounting surface which is one surface of the light receiving element 2.

In the present embodiment, the opening area of the hole 9a is larger than the area of the mounting surface, which is one surface of the light emitting element 1, and is smaller than that of the recessed part, which is the light emitting element mounting section 3c on which the light emitting element 1 is mounted. Designed to be smaller than the area of the back.

Also, in FIG. 2, the side surfaces of the holes 9a and 9b of FIG. 1 and the back surface of the light emitting element mounting portion 3c and the back surface of the light receiving element mounting portion 3d exposed by the holes 9a and 9b. The corners are rounded to 9c and 9d.

Alternatively, although not shown, the shape of the holes 9c and 9d is such that the widths of the back surface of the light emitting element mounting portion 3c and the back surface of the light receiving element mounting portion 3d exposed by the holes 9c and 9d are narrow. It may have a tapered shape in which the width increases as the distance from the back surface increases.

The holes 9a to 9d are formed in a mold for forming the primary mold, for example, so that the holes 9a to 9d are formed. Are formed at the same time.

As described above, in the present embodiment, the heat generated in the light emitting element 1 and the light receiving element 2 is transferred to the light emitting element mounting portion 3c.
Holes 9a and 9 from the back surface of the light receiving element mounting portion 3d.
Since the heat is transmitted to the secondary mold resin 7 that satisfies the condition “b” and further radiated to the outside, the heat radiation of the entire optical coupling device can be further improved. Therefore, even if the size of the light receiving element 2 is reduced to reduce the size of the package made of the secondary mold resin 7 and the amount of generated heat is increased, since the heat radiation is excellent, malfunctions due to the generated heat and damage to components are caused. It is possible to provide an optical coupling device which is small and has excellent heat dissipation, in which various problems occur.

By making the area of the hole 9b smaller than the area of the mounting surface, which is one surface of the light receiving element 2,
It is possible to prevent the light receiving element 2 from being damaged by suppressing the influence of the bending pressure of the light receiving side lead frame 3b, and to obtain a sufficient heat radiation effect.

The opening area of the hole 9a for exposing the back surface of the light emitting element mounting portion 3c is larger than the area of the mounting surface which is one surface of the light emitting element 1 and smaller than the area of the mounting surface which is one surface of the light receiving element 2. By doing so, it is possible to suppress the influence of the bending pressure of the light emitting side lead frame 3a, prevent the light emitting element 1 from being damaged, and obtain a sufficient heat radiation effect.

In the step of filling and molding the outer periphery of the primary mold resin 6 with the secondary mold resin 7, the side surfaces of the holes 9c and 9d and the light emitting element mounting portion 3c exposed by the holes 9c and 9d are formed. The secondary mold resin 7 extends to the corner where the back surface and the back surface of the light receiving element mounting portion 3d are in contact.
Can be sufficiently filled, thereby preventing the generation of air voids and preventing the voids from filling the corners with the secondary mold resin 7 and reducing the heat radiation. .

The holes 9a to 9d are provided so as to expose the back surfaces of the light emitting element mounting section 3c and the light receiving element mounting section 3d, but the present invention is not limited to this.
That is, the light emitting element mounting portion 3c and the light receiving element mounting portion 3d may be provided so as to be formed very thin without exposing the back surfaces thereof.

[Second Embodiment] As a second embodiment, an optical coupling device provided with a plurality of holes according to the first embodiment will be described with reference to the front views of the main components shown in FIGS.

In FIGS. 3 and 4, the same parts as those in FIGS. 1 and 2 showing the first embodiment are denoted by the same reference numerals. In addition, only points different from the first embodiment will be described, and description of similar parts will be omitted.

In FIGS. 3 and 4, the primary mold resin 6 has a plurality of holes exposing the back surfaces of the light-emitting element mounting portions 3c of 9e and 9g and the back surfaces of the light-receiving element mounting portions 3d of 9f and 9h. Are provided.

In FIG. 3, in the step of filling and molding the outer periphery of the primary molding resin 6 with the secondary molding resin 7 using a molding die or the like, the light emitting element mounting portion exposed by the holes 9e and 9f. 3c, the back surface of the light receiving element mounting portion 3d is directly in contact with the secondary mold resin 7.

In FIG. 4, the side surfaces of the holes 9e and 9f in FIG. 3 and the back surface of the light emitting element mounting portion 3c and the back surface of the light receiving element mounting portion 3d exposed by the holes 9e and 9f are shown. The corners were rounded to 9g, 9h.

Alternatively, although not shown, the shape of the holes 9g and 9h is such that the widths of the back surface of the light emitting element mounting portion 3c and the back surface of the light receiving element mounting portion 3d exposed by the holes 9g and 9h are narrow. It may have a tapered shape in which the width increases as the distance from the back surface increases.

The holes 9e to 9h can be formed in the mold for primary molding, for example, by forming a shape such that the holes 9e to 9h are formed in the molding die. Are formed at the same time.

As described above, in the present embodiment, a plurality of holes 9e are provided in the primary mold resin 6, and the back surface of the light emitting element mounting portion 3c and the secondary mold resin 7 filling the plurality of holes 9e are formed. By increasing the contact area, heat dissipation can be further improved. This also means that
Since the contact area between the primary mold resin 6 and the secondary mold resin 7 is also increased, the adhesion can be improved, and the heat generated from the light emitting element can be easily transmitted, so that the heat dissipation can be further improved.

In the step of filling the outer periphery of the primary molding resin 6 with the secondary molding resin 7 using a molding die or the like and performing molding, the side surfaces of the holes 9g and 9h and the holes 9g and 9h are used. Since the light-shielding resin 7 can be sufficiently filled up to the corner where the exposed back surface of the light-emitting element mounting portion 3c and the back surface of the light-receiving element mounting portion 3d are in contact, it is possible to prevent the generation of air voids, It is possible to prevent the corner portions from being filled with the light-shielding resin 7 due to the voids, thereby reducing heat radiation.

The holes 9e to 9h are provided so as to expose the back surfaces of the light emitting element mounting portion 3c and the light receiving element mounting portion 3d, but the present invention is not limited to this.
That is, the light emitting element mounting portion 3c and the light receiving element mounting portion 3d may be provided so as to be formed very thin without exposing the back surfaces thereof.

[Third Embodiment] As a third embodiment, an optical coupling device in which an insulating member is arranged in a hole of the first embodiment will be described with reference to the front views showing the main components of FIGS. I do.

In FIGS. 5 and 6, the same parts as those in FIG. 1 showing the first embodiment are denoted by the same reference numerals.
In addition, only points different from the first embodiment will be described, and description of similar parts will be omitted.

In FIGS. 5 and 6, reference numeral 10 denotes an insulating member such as ceramic having a higher heat radiation property than the primary molding resin 6.

The insulating member 10 is made of a considerable amount (for example, about 80 to 90% (weight ratio)) of silica (crystalline silica or fused silica obtained by subjecting the crystalline silica to a heat treatment or the like) in order to enhance heat dissipation. A light-shielding resin containing the above filler is used.

In FIGS. 5 and 6, the insulating members 10 are arranged so as to be in contact with the back surfaces of the light emitting element mounting portion 3c and the light receiving element mounting portion 3d exposed by the holes of the primary mold resin 6, respectively. The outer periphery is filled with a secondary molding resin 7 using a molding die or the like, and molded.

Alternatively, before the light emitting element 1 and the light receiving element 2 are molded with the primary molding resin 6,
The insulating member 10 is disposed so as to be in contact with the back surface of the light-receiving element mounting portion 3d and the back surface of the light-receiving element c, and the outer periphery thereof is molded with a primary molding resin 6 using a molding die or the like. The outer periphery may be filled with the secondary molding resin 7 and molded.

At this time, if the thickness of the insulating member 10 is set such that a part of the insulating member 10 is exposed on the surface of the secondary mold resin 7, the optical coupling device as shown in FIG. Become. When the thickness of the insulating member 10 is set so that a part of the insulating member 10 is exposed on the surface of the primary mold resin 6, an optical coupling device as shown in FIG. 6 is obtained.

Normally, when the contact area between the insulating member 10 and the back surface of the light receiving element mounting portion 3d is larger than the area of the mounting surface, which is one surface of the light receiving element 2, the primary molding resin 6
In the step of molding and forming, the primary mold resin 6 and the light receiving side lead frame 3 in the cooling step after thermosetting are used.
b, the light receiving side lead frame 3b bends in the direction of the insulating member 10 and the light receiving element 2
May be cracked under the influence of the deflection pressure. Therefore, the contact area between the insulating member 10 and the back surface of the light receiving element mounting portion 3d is designed to be smaller than the area of the mounting surface, which is one surface of the light receiving element 2.

The size of the inner circumference of the contact surface between the insulating member 10 and the back surface of the light receiving element mounting portion 3d is such that it does not protrude from the outer circumference of the mounting surface, which is one surface of the light receiving element 2, and fits inside. It is preferred that

On the other hand, the size of the light emitting element 1 is smaller than that of the light receiving element, for example, 0.28 mm × 0.28 mm × 0.28 mm.
Further, the light-emitting side lead frame 3 is pre-coated with a transparent silicone resin 4 and further has a thickness of, for example, about 0.2 mm.
Since a concave portion (recess) is formed in a part of “a” and is mounted as the light emitting element mounting portion 3c, the influence of the pressure of the deflection of the light emitting side lead frame 3a applied to the light emitting element 1 is considerably reduced. The contact area between the insulating member 10 and the back surface of the light emitting element mounting portion 3c is designed to be larger than the area of the mounting surface which is one surface of the light emitting element 1 and smaller than the area of the mounting surface which is one surface of the light receiving element. .

In the present embodiment, the insulating member 10
The contact area between the light-emitting element mounting portion 3c and the back surface of the light-emitting element mounting portion 3c is larger than the area of the mounting surface, which is one surface of the light-emitting element 1, and smaller than the area of the back surface of the concave portion which is the light-emitting element mounting portion 3c on which the light emitting element 1 is mounted. It is designed.

As described above, in the present embodiment, a material having better heat conductivity than the light-shielding resin can be used as the insulating member. Is generated by the light emitting element mounting portion 3a
To the insulating member 10 having higher heat radiation than the primary mold resin 6 in contact with the back surface of the light receiving element mounting portion 3b and the back surface of the light receiving element mounting portion 3b. Therefore, the heat dissipation of the entire optical coupling device can be further improved. Therefore, even if the size of the light receiving element 2 is reduced to reduce the size of the package made of the secondary mold resin 7 and the amount of heat generation increases,
Since it has excellent heat dissipation, it is possible to provide an optical coupling device which is small and has excellent heat dissipation, which causes various problems such as malfunction due to heat generation and damage to components.

In FIG. 6, heat generated in the light emitting element 1 and the light receiving element 2 is transferred to the primary mold resin 6 in contact with the back surface of the light emitting element mounting portion 3a and the back surface of the light receiving element mounting portion 3b.
Since the heat is transmitted to the insulating member 10 having a higher heat radiation property, the heat is transmitted to the secondary mold resin 7 without passing through the primary mold resin 6, and the heat is radiated to the outside, so that the heat radiation of the entire optical coupling device can be further improved. it can. Further, as compared with the optical coupling device of FIG. 5, moisture and the like do not enter from the gap between the surface of the secondary mold resin 7 and the insulating member 10, so that the entry of the moisture and the like can be easily prevented.

Further, by making the contact area between the insulating member 10 and the back surface of the light receiving element mounting portion 3d smaller than the area of the mounting surface which is one surface of the light receiving element 2, the deflection of the light receiving side lead frame 3a is reduced. Light receiving element 2 with reduced influence of pressure
Can be prevented and a sufficient heat radiation effect can be obtained.

The insulating member 10 and the light emitting element mounting portion 3
c has a larger contact area with the back surface than the area of the mounting surface, which is one surface of the light emitting element 1, and emits light from the insulating member 10 with the insulating member 10 more than the area of the back surface of the concave portion which is the light emitting element mounting portion 3 c on which the light emitting element 1 is mounted. By reducing the contact area with the back surface of the element mounting portion 3c, it is possible to suppress the influence of the bending pressure of the light emitting side lead frame 3b, prevent the light emitting element 1 from being damaged, and obtain a sufficient heat radiation effect. It becomes possible.

[0072]

As described above, according to the optical coupling device of the present invention, the heat generated from at least one of the light emitting element and the light receiving element is transferred from the back surface of the light emitting element mounting portion or the back surface of the light receiving element mounting portion to the hole. Is transmitted to the light-shielding resin that satisfies the conditions described above, and further radiated to the outside, so that the heat radiation of the entire optical coupling device can be further improved. Therefore, even if the size of the light receiving element is reduced in order to reduce the size of the package made of the light-shielding resin and the amount of heat generation is increased, the heat radiation is excellent.
It is possible to provide an optical coupling device which is small and has excellent heat dissipation, in which various problems such as a malfunction due to heat generation and breakage of components occur.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a schematic configuration of an optical coupling device according to a first embodiment of the present invention.

FIG. 2 is a side sectional view showing a schematic configuration of the optical coupling device according to the first embodiment.

FIG. 3 is a side sectional view showing a schematic configuration of an optical coupling device according to a second embodiment.

FIG. 4 is a side sectional view showing a schematic configuration of an optical coupling device according to a second embodiment.

FIG. 5 is a side sectional view illustrating a schematic configuration of an optical coupling device according to a third embodiment.

FIG. 6 is a side sectional view showing a schematic configuration of an optical coupling device according to a third embodiment.

FIG. 7 is a side sectional view showing a schematic configuration of a conventional optical coupling device.

[Explanation of symbols]

Reference Signs List 1 light emitting element 2 light receiving element 3a light emitting side lead frame 3b light receiving side lead frame 3c light emitting element mounting part 3d light receiving element mounting part 6 primary molding resin (translucent resin) 7 secondary molding resin (light shielding resin) 9a, 9b , 9c, 9d, 9e, 9f, 9g, 9h Hole 10 Insulating member

Claims (6)

[Claims] 1. A light-emitting element, a light-receiving element, a light-emitting side lead frame provided with a light-emitting element mounting portion for mounting the light-emitting element, and a light-receiving side lead frame provided with a light-receiving element mounting section for mounting the light receiving element. Covering a part of the light emitting side lead frame and the light receiving side lead frame while covering the light emitting element and the light receiving element,
A light-transmitting resin having a hole at a position corresponding to at least one surface of the back surface of the light-emitting element mounting portion or the back surface of the light-receiving element mounting portion, and a light-shielding resin covering the outer periphery of the light-transmitting resin. An optical coupling device. 2. The optical coupling device according to claim 1, wherein a corner portion in contact with a side surface and a bottom surface of the hole is rounded. 3. The optical coupling device according to claim 1, wherein the shape of the hole is tapered such that the width on the bottom surface side is narrow and the width increases as the distance from the bottom surface increases. Optical coupling device. 4. The optical coupling device according to claim 1, wherein an insulating member is disposed in the hole. 5. The optical coupling device according to claim 5, wherein a part of the insulating member is exposed on a surface of the light shielding resin. 6. The optical coupling device according to claim 1, wherein an opening area of the hole is larger than an area of a mounting surface, which is one surface of the light emitting element, and is one surface of the light receiving element. An optical coupling device having a smaller area than a mounting surface.