JP2568164Y2 - Multiple optical coupling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an optical coupler (photocoupler), and more particularly to a multiple optical coupler having a plurality of light receiving elements.

<Prior Art> In recent years, there has been a demand in the market for a multiple-type optical coupling device with a reduced number of pins in order to reduce the size of an optical coupling device (photocoupler), that is, to improve the mounting density.
For example, isolation between input and output in a programmable controller requires 64 or more optical coupling devices.

However, as shown in FIG. 3, assuming that four light-emitting elements 1 and four light-receiving elements 2 which are normally opposed to each other are connected,
The number of terminals will be 20. In particular, the number of terminals on the light receiving element 2 side is twelve. Therefore, a failure occurs in increasing the mounting density of the entire optical coupling device.

Therefore, in a device having a plurality of light receiving elements 2, it is conceivable to reduce the number of terminals by using a common lead. In other words, as shown in FIG. 4, the power supply terminal Vcc and the ground terminal GND of the light receiving element 2 which is a double optical IC are made common leads and the number of terminals is determined based on the size of the standard DIP (package) and the size of the light receiving element. Some have two output terminals Vo.

In FIG. 4, 3 indicates a bonding wire, and 4 indicates a bent portion of the lead terminals Vcc, GND, Vo1, Vo2.

<Problem to be Solved by the Invention> In the case of the lead frame shown in FIG. 4, a shape that enables wire bonding from a plurality of light receiving elements 2 using the power supply terminal Vcc and the ground terminal GND as common leads is required.

However, unlike a lead frame such as an IC, the optical coupling device requires a bent portion 4 (offset) in the lead frame to secure a light receiving / emitting distance, and the bending accuracy of the bent portion 4 of the lead terminals Vcc and GND. Greatly affects the accuracy of the optical coupling device. That is, if an error occurs in the bending dimension of the bent portion 4, the light receiving element mounting piece (header portion) 7a
And the connection piece 7b is supported by only one lead terminal GND and Vcc, respectively, so that the facing distance between the opposed light receiving and light emitting elements is easily increased, and the light detection accuracy and the withstand voltage of the light receiving element 2 change. It's easy to do. And lead terminals Vcc, GND
The farther the distal end portion 5 is from the proximal end portion 6, the more the distal end portion 5
The change of the facing distance between the light receiving and the light emitting becomes large, so that it is difficult to extend the common leads Vcc and GND any longer in order to ensure the normal operation of the optical coupling device.

In addition, in the case of FIG. 4, the ground wire 3a needs to be attached to the header 7a of the ground terminal GND for mounting the light receiving element 2, and the wire bonding is difficult around the light receiving element 2 to which the Ag paste is attached. It is necessary to separate the lead terminal Vcc from the light receiving element by leaving a gap between the terminal GND connection portion 8 and the lead terminal Vcc, and the tip 5 of the GND is further separated from the base 6 so that the common lead Vcc is no longer provided. , GND
Is even more difficult to extend.

Under the above-described restrictions, it is difficult to form an optical coupling element by simultaneously sealing more than two light receiving elements 2 in order to realize a downsized optical coupling device.

In order to reduce the number of terminals, a method in which two or more circuits shown in FIG. 4 are juxtaposed and a total of four or more light receiving elements 2 are arranged on the same axis can be considered. The work of setting the mold is very complicated, and the work efficiency is reduced. At the same time, there is a drawback that the accuracy cannot be improved.

The present invention has been made in view of the above problems, and has as its object to provide an optical coupling device that can be reduced in size by reducing the number of terminals and that has a stable structure with a constant facing distance between light receiving and emitting.

<Means for Solving the Problem> As shown in FIGS. 1 and 2, the problem solving means according to the present invention comprises a plurality of light emitting elements 11 mounted on a light emitting side lead frame having a bent portion 19, In a multiple optical coupling device in which a plurality of light receiving elements 12 mounted on a light receiving side lead frame 14 having a portion 19 are arranged oppositely and optically coupled in a multiple way, the light receiving side lead The frame 14 is a common light receiving element mounting piece 14 on which the light receiving elements 12 are mounted in a multiple
e, a ground terminal 14a having the bent portion 19,
The ground terminal 14a supports the light receiving element mounting piece 14e at two points on the left and right sides in the direction in which the light receiving elements 12 are juxtaposed and serves as a common lead.

<Operation> In the above-mentioned means for solving the problems, in manufacturing the optical coupling device, the light emitting element 11 is mounted on the light emitting side lead frame and the plurality of light receiving elements 12 are mounted on the light receiving side lead frame 14.
Are mounted in a multiple connection, and after each is internally connected, the light emitting element 11
And the light receiving element 12 are opposed to each other and are sealed with a resin.

At this time, since the ground terminal 14a is a common lead that supports the light-receiving element mounting piece 14e at two points on the left and right, even when the light-receiving element 12 is a multiple type of three or more, only one light-receiving element mounting piece is required. The bending accuracy of the light-receiving-side lead frame 14 is less likely to cause an error than in the conventional example supported by the above. This makes it possible to easily maintain a constant light receiving / emitting distance between the light emitting element 11 and stabilize the light detection accuracy of the light receiving element 12 and the withstand voltage of the optical coupling device.

Therefore, the number of terminals can be reduced and high-density mounting becomes possible, and not only can the package size be reduced,
A stable structure can be obtained.

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing the shape of a lead frame in an optical coupling device according to an embodiment of the present invention, and FIG. 2 is a connection diagram of the optical coupling device.

In general, an optical coupling device (photocoupler) used for an I / O section of a programmable controller uses a mechanical relay for an input on a light emitting element side, so that a light receiving element is set so that generated chattering is canceled by a light receiving element on an output side. The light receiving photodiode and the delay circuit are integrated into one chip.

A light emitting unit and a light receiving unit are provided in the same package. The light emitting unit temporarily converts the electric signal into light, and the light receiving unit converts the light into an electric signal again.

As shown, the optical coupling device of the present embodiment includes a plurality of (four) light emitting elements 11 (light emitting diodes) mounted on a light emitting side lead frame (not shown) and a light receiving side lead frame.
A plurality (four) of light receiving elements 12 mounted on 14 are arranged to face each other, and these are optically coupled in a multiple system.

As shown in FIG. 1, the light receiving side lead frame 14 includes a pair of ground terminals (GND) 14a on which the light receiving element 12 is mounted,
Four output terminals (Vo1 to Vo4) 14b connected to the output electrode of the light receiving element 12 via a bonding wire 18, a pair of power terminals (Vcc) 14c at both ends, and these lead terminals 14a and 14b. , And a tie bar 14d that cantileverly supports 14c.

The ground terminal 14a is a common lead that supports one common light receiving element mounting piece 14e at two points on the left and right, and the power terminal 14c is a connection piece that is routed around the mounting piece 14e.
14f is supported at two points on the left and right sides and is a common lead.

The light-receiving element mounting piece 14e, the four light-receiving elements 12 are die-bonded, and since the common lead is elongated and formed to have a large area, shrinkage of the lead due to thermal expansion becomes a problem. A hole 16 for preventing shrinkage is formed in a portion other than the area where the light receiving element 12 is die-bonded.

The mounting piece 14e is internally connected to the ground electrode portion of the light receiving element 12 via the bonding wire 18, and the power supply terminal 14c
Are internally connected to an input electrode portion of the light receiving element 12 by a bonding wire 18. Thus, a circuit as shown in FIG. 2 is formed.

In the drawing, reference numeral 19 denotes a bent portion provided on each of the lead terminals 14a, 14b, 14c in order to secure a light receiving / emitting distance, and the lead terminal numbers in FIG. 1 correspond to those in FIG. I have.

 The optical coupling device is manufactured as follows.

First, the light emitting element 11 is mounted on the light emitting side lead frame, and the light receiving element 12 is mounted on the light receiving side lead frame 14.

Next, as shown in FIG. 1, an internal connection is made between the electrode portion of the light receiving element 12 and each lead terminal 14a, 14b, 14c of the light receiving side lead frame 14 by using a bonding wire 18.

At this time, one light receiving element mounting piece 14e is connected to the ground terminal 1.
At 4a, it is supported at two points on the left and right to form a common lead, and the connection piece 14f
Are supported by the power supply terminal 14c at two points on the left and right sides to form a common lead. As shown in FIG. 1, the four light receiving elements 12 are connected to Vcc,
Wire layout with common GND is possible.

Thereafter, both lead frames are set in a mold so that the light emitting element 11 and the light receiving element 12 face each other, and a transparent silicone resin is filled between the pair of the light emitting element 11 and the light receiving element 12 to form an optical path. Then, transfer molding is performed using an opaque epoxy resin. Alternatively, each pair of the light emitting element 11 and the light receiving element 12 is sealed with a translucent epoxy resin, and then double transfer molded with an opaque epoxy resin to complete the optical coupling device.

As described above, the ground terminal 14a is connected to the light receiving element mounting piece 14e.
Are supported at two points on the left and right sides to form a common lead. Therefore, even when the light receiving element 12 is a multiple type of three or more, the light receiving element mounting piece shown in FIG. 4 is supported at only one point as in the conventional example. The bending accuracy of the bending portion 19 of the light receiving side lead frame 14 is less likely to occur, and the light receiving and emitting distance between the light emitting element 11 and the light receiving element 12 can be easily kept constant. The dielectric strength of the optical coupling device can be stabilized.

Therefore, the number of terminals can be reduced to enable high-density mounting, and not only can the package size be reduced,
A stable structure can be obtained.

It should be noted that the present invention is not limited to the above embodiment, and it is needless to say that many modifications and changes can be made to the above embodiment within the scope of the present invention.

For example, in the above embodiment, four light receiving elements are provided, but three or five or more light receiving elements may be provided. Here, in particular, when the light receiving elements are provided in six or eight stations, the number of terminals is greatly reduced as compared with the case where a plurality of the conventional dual common leads shown in FIG. 4 are used. The size can be dramatically reduced.

<Effects of the Invention> As is apparent from the above description, according to the present invention, the light-receiving-side lead frame includes a common light-receiving element mounting piece on which the light-receiving elements are mounted in a multiple sequence, and a ground terminal having a bent portion. And the ground terminal is used as a common lead by supporting the light-receiving element mounting piece at two points on the left and right sides in the direction in which the light-receiving elements are juxtaposed, so that the number of terminals can be reduced. Also, when a multiple type of three or more is used, errors in bending accuracy of the lead frame on the light receiving side are less likely to occur compared to the conventional example in which the light receiving element mounting piece is supported at only one point,
The light receiving / emitting distance between the light emitting element and the light emitting element can be easily kept constant, and the light detection accuracy of the light receiving element and the withstand voltage of the optical coupling device can be stabilized.

Therefore, as the number of units increases, the number of terminals can be greatly reduced and high-density mounting becomes possible, and not only can the package size be dramatically reduced, but also a stable structure can be obtained. Has an excellent effect.

[Brief description of the drawings]

FIG. 1 is a plan view showing the shape of a lead frame in an optical coupling device according to an embodiment of the present invention, FIG. 2 is an internal connection diagram of the optical coupling device, and FIG. 3 is an internal connection diagram of a conventional optical coupling device. FIG. 4 is a plan view showing the shape of a lead frame in another conventional example. 11: light emitting element, 12: light receiving element, 14: light receiving side lead frame, 14a: ground terminal, 14e: light receiving element mounting piece.

Continuation of the front page (56) References JP-A-55-44716 (JP, A) JP-A-60-41270 (JP, A) JP-A-59-132176 (JP, A) JP-A-60-68678 (JP) , A) Japanese Utility Model Showa 54-103763 (JP, U) JP-B 56-45303 (JP, B2)

Claims (1)

(57) [Scope of request for utility model registration] 1. A plurality of light emitting elements mounted on a light emitting side lead frame having a bent portion and a plurality of light receiving elements mounted on a light receiving side lead frame having a bent portion are arranged opposite to each other. In the multiple optical coupling device in which these are optically coupled in a multiple system, the light receiving side lead frame includes a common light receiving element mounting piece on which the light receiving elements are mounted in a multiple system, and the bending. And a ground terminal provided with a portion, the ground terminal supporting the light receiving element mounting piece at two right and left points in the direction in which the light receiving elements are juxtaposed and serving as a common lead. Optical coupling device.