JP2002141549A - Photocoupler and method for manufacturing photocoupler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocoupler capable of reducing a decrease in an optical coupling efficiency and a method for manufacturing the photocoupler. SOLUTION: The photocoupler comprises a light transmissive resin interposed between a light emitting element and a photodetector disposed oppositely to each other. The photocoupler further comprises a space disposed substantially oppositely to the photodetector and provided in the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocoupler and a method of manufacturing a photocoupler, and more particularly to a structure of an optical coupling (coupling) portion of an SSR (semiconductor relay) and a method of manufacturing a photocoupler.

[0002]

2. Description of the Related Art In a conventional photocoupler, as shown in FIGS. 6, 7 and 8, a photodiode chip 1 serving as a light receiving element is first provided on an output side frame 170.
20 is placed, and a silicone resin 140 as a translucent resin is potted on the
The LED chip 110 which is a light emitting element mounted on the input side frame 160 is buried approximately at the center of the top of the zero.

[0003] The photodiode chip 120 is electrically connected to the output frame 170 by wires 131, and the LED chip 110 is electrically connected to the input frame 161 by wires 130.

The frames 170, 160, 161 containing both chips 110, 120 generated in this way.
And wires 130 and 131, transparent silicone resin 14
Mold resin 1 so as to cover all the optical coupling portions made of
50 is filled to complete the photocoupler.

In the photocoupler completed in this manner, the internal space 180 is formed inside the silicone resin 140 due to the cooling of the silicone resin 140 and the effect of the material and temperature of the high-temperature mold resin 150 filling the outside.
Occurs.

The internal space 180 may be formed at the interface between the mold resin 150 and the silicone resin 140 as shown in FIG. 6, or may be formed at the hollow inside of the silicone resin 181 as shown in FIG. Also, as shown in FIG. 8, the mold resin 150 and the silicone resin 14
An internal space 183 may be generated at the interface with zero.

In the photocoupler thus generated, the input LED chip 110 and the output photodiode chip 120 are electrically insulated, and the LED chip 110 and the photodiode chip 120 are separated.
A signal by a light beam can be transmitted through the translucent silicone resin 140 therebetween.

[0008]

However, in the above-described photocoupler and the method of manufacturing the photocoupler, the optical coupling portion is formed by filling a translucent silicone resin between the LED chip and the photodiode chip. The outside is often covered with mold resin.

At this time, as shown in FIG. 6, FIG. 7, and FIG. 8 described in the related art, internal spaces 180 and 181 are created inside due to a difference in thermal expansion coefficient between the silicone resin 140 and the mold resin 150.

If this space is formed at the interface between the silicone resin 140 and the mold resin 150, the difference in the refractive index increases, the reflectance at the interface of the silicone resin 140 is improved, and the optical coupling efficiency is improved. On the other hand,
As shown in FIG. 8, if a space is formed at the interface, the space between the input side frame 161 and the wire 161 and the space between the output side frame 170 and the wire 131 extend over the internal space 183 to maintain insulation. This causes a problem that the breakdown voltage between the input and the output decreases.

On the other hand, as shown in FIGS. 6 and 7, when internal spaces 180 and 181 are formed inside the transparent silicone resin 140, the input / output withstand voltage at the interface increases, but a difference in refractive index occurs. Photodiode chip 120 for
The light quantity is remarkably reduced in a part of the light receiving cell (directly below the internal spaces 180 and 181).

Here, the photo diode chip 120
Is usually a light receiving cell driven by another element, and the output voltage is obtained by connecting several to several tens of light receiving cells of the photodiode chip 120 in series. However, there is a problem that the light coupling efficiency is reduced because the light receiving cell is limited to the light receiving cell having the smallest current.

Therefore, when the LED chip and the photodiode chip are insulated and arranged at a predetermined interval by using a translucent silicone resin, it is possible to eliminate the influence on the wires and the like mounted inside the LED chip and the photodiode chip. There is a problem to be solved in a photocoupler and a photocoupler manufacturing method capable of improving the light transmission state.

[0014]

In order to solve the above problems, a photocoupler and a method of manufacturing a photocoupler according to the present invention are configured as follows.

(1) A photocoupler formed by interposing a light-transmitting resin between a light-emitting element and a light-receiving element that are arranged to face each other, wherein the light-receiving element has substantially the light-receiving element inside the light-transmitting resin. A photocoupler characterized by providing a space portion facing the entire surface.

(2) The light emitting element is connected to an input side frame by a wire, and the light receiving element is connected to an output side frame by a wire, and a wire connected to the light emitting element and a wire connected to the light receiving element are connected. The photocoupler according to (1), wherein at least one of the photocouplers is not arranged inside the space.

(3) The first translucent resin is filled on the output side frame on which the light receiving element is mounted so that the light receiving element is an amount that is buried in the entire filling amount and the top portion has a curved surface shape. Then, the filled first translucent resin is cured at a predetermined temperature, the remaining second translucent resin is filled again on the cured first translucent resin, and the refilled second translucent resin is filled. An input-side frame on which a light-emitting element is mounted is mounted on the upper part of the second light-transmitting resin, and the second light-transmitting resin on which the input-side frame is mounted is cured at a predetermined temperature to generate an optical coupling portion. A high-temperature mold resin is filled by transfer molding so as to cover the periphery of the optical coupling portion, the filled mold resin is cooled, and the first light-transmissive resin and the second light-transmissive resin are cooled. A space characterized by forming a space at the interface. Coupler manufacturing method.

(4) The light receiving element is electrically connected to the output side frame by a wire, and the light emitting element is electrically connected to the input side frame by a wire. The photocoupler manufacturing method according to (3), wherein at least one of the wires connected to the light receiving element is not arranged inside the space.

(5) A light emitting element electrically connected to the input side frame by a wire, a light receiving element arranged opposite to the light emitting element and electrically connected to the output side frame by a wire, A light-transmitting resin filled between the light-receiving element and a mold resin covering the input-side frame, the output-side frame, and the light-transmitting resin; A photocoupler having a space formed at an interface, wherein a wire connected to the light emitting element and a wire connected to the light receiving element are coated with an insulating coating material.

[0020]

Next, various embodiments of a photocoupler and a photocoupler manufacturing method according to the present invention will be described.
This will be described with reference to the drawings.

In the photocoupler according to the first embodiment of the present invention, as shown in FIG. 1, a photodiode chip 120 as a light receiving element is mounted on an output frame 170,
Silicone resins A and B (141 and 190), which are translucent resins, are interposed between the input side frames 160 and 161 and the LED chips 110 as light emitting elements.

An internal space 182 is provided between the silicone resins A and B (141 and 190), which are light-transmitting resins, as a space disposed so as to face almost the entire surface of the photodiode chip 120. ing.

The internal space 182 contains the LED chip 1
At least one of the wires 130 and 131 connected to the photodiode chip 120 and the photodiode chip 120 is not included in the structure, so that the breakdown voltage between the wires 130 and 131 is prevented from deteriorating.

The inner space 182 and the silicone tree A,
B (141, 190) at the interface with the LED chip 110
Of the light from the photodiode chip 120, the amount of light received by the photodiode chip 120 decreases. However, since the internal space 182 is disposed to face almost the entire surface of the photodiode chip 120, a specific light receiving cell of the photodiode chip 120 is not provided. Only the amount of received light does not decrease, and the decrease in the optical coupling efficiency of the entire photodiode chip 120 decreases.

Then, the photocoupler is completed by covering the periphery of the optical coupling portion formed of the LED chip 110, the silicone resins A and B (141 and 190) and the photodiode chip 120 with the mold resin 150.

Next, a method of manufacturing the photocoupler having the structure shown in FIG. 1 will be described with reference to FIGS.

First, as shown in FIG. 2A, a first silicone resin A (141) is applied on a photodiode chip 120 which is electrically connected to an output frame 170 by wires 131 by a conventional method. A small amount is dropped (in the case of the embodiment, the amount that the photodiode 120 is buried in the entire filling amount and the top portion becomes a curved surface).
Then, curing is performed at a predetermined temperature to cure.

Next, as shown in FIG. 2B, a second silicone resin B (190) is dropped on the cured silicone resin A (141). Next, as shown in FIG. 2 (C), the input side frames 160 and 161 on which the LED chips 110 are mounted are put on the silicone resin B (190) to be combined, cured at a predetermined temperature, and cured. An optical coupling part is formed.

Next, as shown in FIG. 3A, the optical coupling portion is covered with a molding resin 150 by transfer molding so as to cover the optical coupling portion. At this time, FIG.
As shown in (B), since the temperature rises when covering with the mold resin 150, the silicone resins A and B (141, 19
0) expands and then cools, causing the mold resin 15
A space is created due to the difference in the coefficient of thermal expansion from 0, but once the silicone resin A is cured, the silicone resin A
Since the adhesive force at the interface between (141) and the silicone resin B (190) is weak, the silicone resin B (190) adheres to the mold resin 150 and the silicone resin A (141)
182 between the inner space and the silicone resin B (190).
Is generated.

The inner space 182 is filled with an amount of the silicone resin A (141) which has been initially filled so as to cover the photodiode 120, and the surface thereof is formed into a curved surface. The silicone resin A (14
While the adhesive force at the interface between 1) and the silicone resin B (190) is reduced, the high-temperature mold resin 150
When cooled, the silicone resin B (190) is pulled toward the mold resin 150,
Along the curved surface at the interface between (141) and the silicone resin B (190), the inner space 182 having the curved surface is generated.

This internal space 182 has a curved surface shape with respect to the photodiode chip 120 and is disposed so as to face almost the entire surface of the photodiode chip 120. Does not decrease, and the decrease in the optical coupling efficiency of the entire photodiode chip 120 decreases.

Next, a second embodiment of a photocoupler and a photocoupler manufacturing method will be described with reference to FIG.

In the photocoupler of the second embodiment, as shown in FIG. 4, the inner space 183 has a convex curved shape with respect to the photodiode chip 120, and the LED chip 110 and the wires of the photodiode chip 120 have the same shape. It has a structure so that it does not stick. Other manufacturing methods and structures are the same as those in the first embodiment, and thus the same reference numerals are given and the description thereof will be omitted.

Next, a third embodiment of a photocoupler and a photocoupler manufacturing method will be described with reference to FIG.

As shown in FIG. 5, the photocoupler according to the third embodiment is the same in that an optical coupler is generated by the method described in the prior art and that the optical coupling portion is covered with a mold resin 150. In this structure, the wires are separately coated with an insulating coating material to prevent a decrease in the withstand voltage between the wires due to the internal space.

That is, the structure is the same as that of the output side frame 170.
A photodiode chip 120 as a light receiving element is mounted on the upper part, a transparent silicone resin 140 is bonded on the upper part, and an LED chip as a light emitting element mounted on the input side frame 160 at a position substantially at the center of the top of the silicone resin 140. Light receiving cell mounted so as to embed 110.

The photodiode chip 120 is electrically connected to the output frame 170 by wires 131, and the LED chip 110 is electrically connected to the input frame 161 by wires 130.

The frames 170, 160, 16 including both the chips 110, 120 generated in this way.
1 and wires 130 and 131, transparent silicone resin 1
The photo-coupler is completed by filling the mold resin 150 so as to cover all of the optical coupling portion composed of 40.

The wires 130 and 131 are coated with insulating coating materials 210 and 211 in advance, so that even if the wires 130 and 131 face the internal space 184, the pressure resistance of the wires 130 and 131 is increased. Is not reduced.

In the photocoupler thus completed, the internal space 184 is formed inside the silicone resin 140 due to the cooling of the silicone resin 140 and the effect of the material and temperature of the high-temperature mold resin 150 filling the outside.
Occurs.

The inner space 184 is formed by the wires 130, 1
31, the wires 130, 1
Since 31 is coated with an insulating coating material, the pressure resistance and the like do not decrease.

[0042]

As described above, the light-transmitting resin is gradually filled between the light-emitting element and the light-receiving element to form an optical coupler, and the interface between the step-filled light-transmitting resin is formed. Since the space portion is provided in the light receiving element, the light receiving amount of a part of the light receiving element does not decrease, and the decrease in the optical coupling efficiency of the entire light receiving element can be reduced.

Further, by coating the wires of the light-emitting element and the light-receiving element existing in the light-transmitting resin with an insulating coating material, even if they reach the space generated inside the light-transmitting resin, they can be used. This has the effect of preventing the withstand voltage of the wire from being lowered.

[Brief description of the drawings]

FIG. 1 is a sectional view of a photocoupler according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a step of manufacturing the photocoupler in FIG.

FIG. 3 is a sectional view showing a step of manufacturing the photocoupler shown in FIG. 1 as in FIG. 2;

FIG. 4 is a sectional view of a photocoupler according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a photocoupler according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view of a photocoupler according to the related art.

FIG. 7 is a cross-sectional view of a photocoupler according to the related art.

FIG. 8 is a cross-sectional view of a photocoupler according to the related art.

[Explanation of symbols]

 110 LED chip 120 Photodiode chip 130 Wire 131 Wire 141 Silicone resin A 150 Mold resin 160 Input side frame 161 Input side frame 170 Output side frame 182 Internal space 183 Internal space 190 Silicone resin B 210 Insulating coating material 211 Insulating coating material

Claims (5)

[Claims] 1. A photocoupler formed by interposing a light-transmitting resin between a light-emitting element and a light-receiving element which are arranged to face each other, wherein substantially the entire surface of the light-receiving element is provided inside the light-transmitting resin. A photocoupler, wherein a space is provided to face the photocoupler. 2. The light-emitting element is connected to an input-side frame by a wire, and the light-receiving element is connected to an output-side frame by a wire, and at least one of a wire connected to the light-emitting element and a wire connected to the light-receiving element. 2. The photocoupler according to claim 1, wherein one of the photocouplers is not disposed inside the space. 3. An output-side frame on which a light-receiving element is mounted,
The first translucent resin is filled so that the light receiving element is buried in the entire filling amount and the top portion has a curved shape, and the filled first translucent resin is cured at a predetermined temperature. Then, the upper portion of the cured first translucent resin is again filled with the remaining second translucent resin, and the input side frame having the light emitting element mounted on the upper portion of the refilled second translucent resin. And curing the second light-transmitting resin on which the input side frame is placed at a predetermined temperature to form an optical coupling portion, and then cover the periphery of the optical coupling portion with a high-temperature mold resin by transfer molding. And filling the molded resin so as to form a space at the interface between the first light-transmitting resin and the second light-transmitting resin. Production method. 4. The light receiving element is electrically connected to the output side frame by a wire, the light emitting element is electrically connected to the input side frame by a wire, and the wire connected to the light emitting element and the light receiving element are connected. 4. The method according to claim 3, wherein at least one of the wires connected to the element is not disposed inside the space. 5. A light emitting element electrically connected to an input side frame by a wire, a light receiving element disposed opposite to the light emitting element and electrically connected to an output side frame by a wire, and the light emitting element and the light receiving element. A translucent resin to be filled between the translucent resin and an element; and a mold resin covering the input side frame, the output side frame, and the translucent resin, and an interface between the translucent resin and the mold resin. Wherein a wire connected to the light emitting element and a wire connected to the light receiving element are coated with an insulating coating material.