JP2981371B2 - Optical coupling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coupling device for transmitting input and output by light.

[0002]

2. Description of the Related Art In recent years, the market demand for optical coupling devices (photocouplers) has been remarkable, and in particular, the penetration rate of dual in-line package (DIP) type optical coupling devices in which a light-transmitting resin and a light-shielding resin are double-molded is increasing. However, as electronic components have become smaller and thinner, the demand for surface mount (SMD) types has also increased, and small SMD types have been developed and become more widespread.

[0003] However, the demand for the above-mentioned miniaturization and thinning is further advancing. However, since it has a lead frame, its dimensions must be secured to some extent in consideration of its strength and the like, and miniaturization of the SMD type optical coupling device has reached its limit.

[0004] In response to this trend, leadless couplers are also under development, and a package using a film carrier system with further reduction in thickness is desired.

[0005] One of the structures of the optical coupling device adopting the film carrier system is as shown in FIG. 8, in which an infrared light emitting diode as a light emitting element is provided on the same plane of a light transmitting insulating film 1 (tape carrier). 2 and a phototransistor 3 as a light receiving element.

Since the light emitting element 2 has an upper electrode (anode or cathode) and a back electrode (cathode or anode), it is laid out in a vertical direction with respect to the film carrier in surface mounting, and both electrodes are electrically and mechanically made of Ag paste or the like. Make a connection. The light receiving element 3 is surface-bonded to a chip that has been subjected to bump processing (not shown). This bump has
Au or solder is used.

As the tape material of the insulating film 1, a resin material such as polyimide, polyester, or glass epoxy is used. The copper foil or the rolled copper of the conductor pattern formed on the insulating film 1 is used to punch a hole in the tape, then the tape is laminated and patterned by etching.

After the light emitting element 2 and the light receiving element 3 are mounted, molding is performed using a light shielding mold resin 4. The mold resin 4 is an epoxy resin granule (E pellet) or the like used in an integrated circuit (IC) assembly process, and is melted by heat and molded. Alternatively, there is a method of molding using a transfer molding technique in order to improve dimensional accuracy in a thin type.

[0009]

In the above-mentioned film carrier type optical coupling device, the insulating film 1 corresponding to the light path of the light emitting element 2 and the light receiving element 3 (hereinafter referred to as an optical path) is made of polyimide resin or the like as described above. To be
The transmittance of the infrared light emitting diode is about 90% when the peak wavelength is around 950 μm, and a design with high light efficiency is possible. However, since the electrode for signal extraction is made of copper foil or the like and a part of the insulating film 1 is integrated as a reinforcing material, the disturbing light 5 is emitted from the light receiving element 3 in the thickness direction of the end of the insulating film 1 or the like. To cause malfunction of the device.

[0010] Accordingly, the applicant has filed a Japanese Patent Application No. 3-31250.
There is an optical coupling device proposed in No. 1 (filed on November 27, 1991).

The optical coupling device is, as shown in FIGS.
A slit 6 is formed in the outer peripheral portion of the insulating film 1 to prevent disturbance light from traveling along the thickness direction of the insulating film 1 and entering the optical path between light receiving and emitting. The slit 6
Is obtained by punching out the periphery of the optical path forming region La of the insulating film 1. However, after the slit 6 is formed, the two regions La and Lb are connected by the connecting portion 7 so that the optical path forming region La of the insulating film 1 is separated from the other region Lb of the insulating film 1 and does not separate. I have. The provision of the connecting portion 7 may cause disturbance light to enter the optical path forming region La from the connecting portion 7. Therefore, a notch 8 is also formed outside the connecting portion 7 to prevent straight light from the outside from traveling along the connecting portion 7 and entering the optical path forming region La.

In the drawing, 2 is a light emitting element, 3 is a light receiving element, 4 is a light-shielding resin, 9 is a light emitting side conductor pattern, 10 is a light receiving side conductor pattern, and 11 is a light receiving side conductor pattern.
Is a reflective film.

According to the above-described conventional example, as shown in FIG. 11, it is possible to prevent the straight light from outside from directly entering the optical path forming region La. However, in the non-optical path forming region Lb and the connecting portion 7, the straight light is reflected by the light-shielding resin 4 or the like.
By repeating the absorption, disturbance light slightly enters the optical path forming region La, which may cause malfunction of the device.

The present invention has been made in view of the above circumstances, and has as its object to provide an optical coupling device capable of preventing a device from malfunctioning due to disturbance light.

[0015]

The optical coupling device of the present invention comprises:
An optical coupling device in which a light emitting element and a light receiving element are arranged to be optically coupled, and the light emitting element and the light receiving element are respectively mounted on a light emitting side conductor pattern and a light receiving side conductor pattern formed on an upper surface of an insulating film. , An opening is provided in at least a mounting portion of each of the light emitting element and the light receiving element in the insulating film, and the light emitting element and the light receiving element are each provided with the light emitting side conductor pattern and the light receiving element that overhang the opening. Characterized by being mounted on the side conductor pattern, providing a light transmitting substance between the light emitting element and the light receiving element, and sealing the light transmitting substance, the light emitting element and the light receiving element with a light shielding resin. It is.

[0016]

According to the above construction, the optical coupling device of the present invention uses a light-transmitting substance as an optical path, and completely separates the light-emitting element and the light-receiving element from each other except for a portion opposed to the light-transmitting substance. Even if disturbing light enters from the thickness direction of the insulating film, it can be prevented that the light emitting element is irradiated by the disturbing light when it is not operating and becomes the same state as emitting light, Further, the light receiving element does not receive disturbance light. Therefore, malfunction of the device due to disturbance light can be prevented.

[0017]

FIG. 1 is a structural view of an optical coupling device showing an embodiment of the present invention. FIG. 1 (a) is a transverse sectional view, and FIG. 1 (b) is a longitudinal sectional view. FIG. 2 is a plan view showing the insulating film before processing, FIG. 3 is a plan view showing a state where openings are formed in the insulating film, and FIG. 4 is a state showing a state where a conductor pattern is formed on the insulating film. 5 is an enlarged sectional view of a portion A in FIG. 4, FIG. 6 is a plan view showing a state in which a light emitting / receiving element and a light transmitting substance are mounted on an insulating film, and FIG. 7 is an insulating film. FIG. 3 is a plan view showing a state in which the light emitting / receiving element and the light transmitting material are sealed with a light shielding resin.

As shown in FIG. 1, in the optical coupling device of this embodiment, a light emitting side conductor pattern 9 and a light receiving side conductor pattern 10 are formed on the upper surface of an insulating film 1, and the light emitting side conductor pattern 9 and the light receiving side conductor pattern 10 are formed. A light-emitting element 2 and a light-receiving element 3 are mounted thereon, and an opening 12 is provided in an entire area of the mounting portion of the light-receiving and light-emitting elements 2 and 3 in the insulating film 1 and in the vicinity thereof, The element 2 and the light receiving element 3 are respectively
Is mounted on the light-emitting side conductor pattern 9 and the light-receiving side conductor pattern 10 which are overhanging on the light-emitting side, and between the light-receiving and light-emitting elements 2 and 3, an insulating film, glass, etc. Light-transmitting substance 13
And the light transmitting substance 13, the light emitting element 2 and the light receiving element 3 are sealed with a light shielding resin 4. still,
In the figure, 8 is a notch.

As shown in FIG. 2, the insulating film 1 is made of a polyimide resin having excellent transparency and heat resistance, and is supplied to the manufacturing process in a state where a plurality of devices are connected in a strip shape. On the lower surface of the insulating film 1, a reflection film 11 for reflecting light obliquely downward from the side of the light emitting element 2 to the light receiving element 3 is formed. The reflection film 11 is made of a copper foil made of the same material as the conductor patterns 9 and 10, and is disposed at least over the entire optical path between the light emitting and receiving elements 2 and 3, as shown in FIG.

Each of the apertures 12 has a size equal to or greater than each of the light emitting and receiving elements 2 and 3, and a resin is injected when the light shielding resin 4 is sealed.

The light emitting element 2 uses an infrared light emitting diode or the like, and the light receiving element 3 uses a phototransistor or the like.

The light emitting side conductor pattern 9 and the light receiving side conductor pattern 10 are formed on the upper surface of the insulating film 1 based on a desired circuit design using a conductive material such as a copper foil, as shown in FIG. ing. The two conductor patterns 9,
The tip of 10 is formed in a substantially L-shape so as to be connected to each electrode of each element 2 and 3, and further the tip is as shown in FIG.
An overhang projecting from the opening 12 of the insulating film 1 is provided so that the elements 2 and 3 can be mounted.

The light transmissive substance 13 only needs to have good transmittance and insulating properties, and may have any shape as long as the light receiving and emitting elements 2 and 3 are optically coupled.
As an example of using glass, silicate glass or the like is used.

As the light-shielding resin 4, a general black epoxy resin having a light absorbing property is used, and as shown in FIG.
It is poured into the upper surface of the insulating film 1 and the opening 12 and is hardened, thereby preventing disturbance light from reaching the light receiving and emitting elements 2 and 3.

Here, as shown in FIG. 1, the penetration of disturbance light 5 from the thickness direction of the insulating film 1 can be considered. However, according to the optical coupling device having the above configuration, the light emitting and receiving elements 2, 3
An optical path is formed by providing a light-transmitting substance 13 between the light-receiving and light-emitting elements 2, 3. Is not affected by That is, when the light emitting element 2 is not operated, the light emitting element 2 can be prevented from being irradiated with the disturbance light 5 to be in the same state as emitting light. Further, the light receiving element 3 receives only the light from the light transmissive substance 13 direction, and thus hardly receives the disturbance light 5. Therefore, malfunction of the device due to disturbance light can be prevented.

A method for manufacturing the optical coupling device having the above configuration will be described.

First, as shown in FIG. 2, an opening 12 and a notch 8 are cut out from a single film carrier tape-shaped insulating film 1 by a punching die to obtain a shape shown in FIG. In the drawing, reference numeral 15 denotes a hole for sealing the outer periphery of the insulating film 1, and reference numeral 16 denotes a resin sealing region.

Then, after the copper foil is uniformly laminated on the insulating film 1, the necessary copper foil is left by etching as shown in FIG.

Thereafter, the copper foil is plated with solder. Since the solder bumps are formed on the light receiving element 3 to be surface-mounted, the solder is used to make an electrical and mechanical connection.

The insulating film 1 thus manufactured
Next, as shown in FIG. 6, an infrared light emitting diode chip as the light emitting element 2 is die-bonded. The light emitting element 2 has electrodes on the upper surface and the rear surface, and is placed on the insulating film 1 in a state where the electrodes are perpendicular to the electrodes, and electrically connected with the Ag paste 14. Leave to stand.

Next, face-down bonding is performed on the phototransistor chip as the light receiving element 3. The electrodes of the light receiving element 3 have been subjected to solder bump processing,
Heat is applied from the back of the insulating film 1 by a heater head,
Connect the solders.

Next, an insulating film as the light transmitting substance 13 is mounted on the insulating film 1 adjacent to the light emitting and receiving elements 2 and 3 using a transparent resin or the like.

The order of mounting the light emitting element 2, the light receiving element 3, and the light transmissive substance may be different from the above order.

After assembling the light emitting element 2 and the light receiving element 3 on the insulating film 1 as described above, resin molding is performed using the light shielding resin 4. Here, the light-shielding resin 4
Performs transfer molding to improve dimensional accuracy for the purpose of thinning. FIG. 7 shows the shape after the molding.

Thereafter, the optical coupling device connected in a tape shape is cut out of a single product plate, and a final product is completed. This state is shown in FIG.

Also, in the above embodiment, a small amount of disturbance light repeatedly reflects and absorbs and travels on the insulating film 1, and this light rises to the light transmitting substance 13 to cause the light emitting element 2 and the light receiving element 3. It is thought that the light-transmitting material 13 may be reached, but by providing an insulating light-reflecting film on the back surface of the light-transmitting material 13, the light-transmitting material 13 does not reach the light-emitting element 2, the light-receiving element 3, and the light-transmitting substance 13. , Can completely prevent the entrance of disturbance light. At this time, the reflection film 11 on the back surface of the insulating film 1 becomes unnecessary.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made to the above-described embodiment within the scope of the present invention.

For example, when a gap is formed between the light emitting element 2 or the light receiving element 3 and the light transmitting substance 13, the gap is filled with a transparent resin or the like.

[0039]

As described above, according to the optical coupling device of the present invention, the light transmitting material is used as the optical path, and each of the light emitting element and the light receiving element has a light shielding property except for the portion opposed to the light transmitting material. Since it is sealed with resin, disturbance light can be prevented from reaching the light emitting element and the light receiving element, and malfunction of the optical coupling device can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, in which FIG. 1 (a) is a transverse sectional view and FIG. 1 (b) is a longitudinal sectional view.

FIG. 2 is a plan view showing an insulating film before processing.

FIG. 3 is a plan view showing a state where holes are formed in an insulating film.

FIG. 4 is a plan view showing a state where a conductor pattern is formed on an insulating film.

FIG. 5 is an enlarged sectional view of a portion A in FIG.

FIG. 6 is a plan view showing a state in which a light emitting / receiving element and a light transmitting substance are mounted on an insulating film.

FIG. 7 is a plan view showing a state in which a light emitting / receiving element and a light transmitting substance on an insulating film are sealed with a light shielding resin.

FIG. 8 is a longitudinal sectional view showing a conventional example.

FIG. 9 is a longitudinal sectional view showing another conventional example.

FIG. 10 is a plan view of the optical coupling device shown in FIG.

11 is a cross-sectional view of the optical coupling device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating film 2 Light emitting element 3 Light receiving element 4 Light shielding resin 9 Light emitting side conductor pattern 10 Light receiving side conductor pattern 12 Opening (part) 13 Light transmissive substance

Claims (1)

(57) [Claims] 1. A light emitting element and a light receiving element are arranged so as to be optically coupled to each other, and the light emitting element and the light receiving element are respectively mounted on a light emitting side conductor pattern and a light receiving side conductor pattern formed on an upper surface of an insulating film. In the optical coupling device, an opening is provided in at least a mounting portion of each of the light emitting element and the light receiving element on the insulating film, and the light emitting element and the light receiving element each overhang the opening. Mounted on the side conductor pattern and the light receiving side conductor pattern, providing a light transmissive substance between the light emitting element and the light receiving element, the light transmissive substance,
An optical coupling device, wherein a light emitting element and a light receiving element are sealed with a light shielding resin.