JP3824696B2 - Photocoupler and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure and manufacturing method of a photocoupler in which a light emitting element and a light receiving element are integrally sealed with a resin.
[0002]
[Prior art]
Photocouplers are widely used in the field of medical equipment as electronic components that transmit electrical signals via optical signals by using light emitting elements and light receiving elements.
As shown in FIG. 5, the conventional photocoupler has a general structure in which a light emitting element 21 and a light receiving element 22 for receiving light generated from the light emitting element 21 are electrically connected to the lead electrodes 23 and 24, respectively. The two elements 21 and 22 are arranged together with lead electrodes 23 and 24 together with a transparent resin such as silicone and an opaque resin 25 that further covers the transparent resin in a surrounding manner. It is formed by sealing integrally.
[0003]
In the photocoupler having such a structure, for example, a light emitting diode (LED) is used as the light emitting element 21, while a phototransistor made of Si is generally used as the light receiving element 22, for example.
The LED 21 used in this type of photocoupler is formed in a split-type bare chip shape in which electrodes are provided oppositely on the front and back surfaces thereof, so that the PN junction surface formed by introducing impurities is the front or back surface. Is formed so as to terminate in parallel with, i.e., on the outer peripheral surface.
[0004]
[Problems to be solved by the invention]
By the way, in the photocoupler of the type described above, the phototransistor 22 is provided in a direction perpendicular to the PN junction surface of the LED chip 21.
However, it is known that in the semiconductor light emitting device composed of the PN junction surface, light emission with higher luminance occurs at the PN junction surface and the vicinity thereof at the time of light emission. It is understood that stronger light emission is produced in the (parallel direction). In addition, since the surface of the LED chip is generally provided with a metal layer as an upper surface electrode as described above, the upward light emission is also structurally hindered.
[0005]
In addition, since the conventional photocoupler has a structure in which the LED chip 21 and the phototransistor 22 are vertically opposed to each other, it is difficult to make the package thinner than a certain level.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a photocoupler and a method for manufacturing the photocoupler that improve the light transmission efficiency while reducing the thickness of the package.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems, a photocoupler according to the present invention includes a light emitting element having a junction surface terminated on a side surface, a light receiving element provided with a light receiving surface on an upper surface, and a first electrically connected to the light emitting element . A first lead electrode having an island; a second lead electrode having a second island opposite to the first island electrically connected to the light receiving element; and a transparent member for sealing the light emitting element and the light receiving element in common. an optical resin, wherein the opaque resin for sealing such a light-transmitting resin covering made, said light emitting element is disposed higher than the upper surface of the bonding surface thereof is the light receiving element, the second island One diagonal extension line of the light emitting element extending toward is fixed to the first island so as to be parallel to the first lead electrode .
[0007]
For this reason, the photocoupler of the present invention can be thinned to about two-thirds in the height direction as compared with the conventional structure. In use, a part of the high-intensity light emitted from the bonding surface of the light-emitting element and its vicinity is reflected toward the upper surface of the light-receiving element at the interface between the light-transmitting resin and the light-impermeable resin, which is favorable. Signal transmission via infrared light can be performed efficiently.
[0008]
The method of manufacturing a photocoupler according to the present invention includes a light emitting element having a junction surface terminating on a side surface, a light receiving element provided with a light receiving surface on an upper surface, a first island for mounting the light emitting element, and the first island. lower, a step of second island for mounting the light receiving element disposed to face the first island to prepare a lead frame provided, one in the light-emitting element which extends toward the second island One of the extension line of the diagonal, the so as to be perpendicular to the first island side, a step of placing each said light emitting element and the light receiving element in the first and second on island, the light emitting element and the light receiving element characterized in that it comprises a step of sealing together a translucent resin bets, the step of applying sealing with opaque resin so as to cover the light-transmitting resin.
[0009]
For this reason, a photocoupler can be easily manufactured by mounting and integrally sealing a light emitting element and a light receiving element on a common lead frame, and a lead frame on which a light emitting element and a light receiving element are mounted as in the conventional method. Can be avoided separately by forming them separately, aligning them with each other through a mold, and sealing with resin.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
With reference to the accompanying drawings, embodiments of the Photo-coupler and a manufacturing method thereof according to the present invention will be described in detail below. As shown in FIG. 1, the photocoupler according to the present invention is electrically connected to the light emitting element 2 having a bonding surface 2 a terminating on the side surface, the light receiving element 3 having a light receiving surface 3 a on the upper surface, and the light emitting element 2. The first lead electrode 4, the second lead electrode 5 electrically connected to the light receiving element 3, the translucent resin 6 that seals the light emitting element 2 and the light receiving element 3 in common, and the light transmitting element 6. And an opaque resin 7 which is sealed so as to cover the optical resin 6.
[0011]
The light emitting element 2 is made of, for example, a GaAs semiconductor substrate, and is provided with a bonding surface 2a extending in parallel to the front surface provided with the front electrode and the back surface provided with the back electrode. The joint surface 2a terminates on the outer peripheral surface provided at a right angle to the front surface or the back surface of the substrate.
The light receiving element 3 is made of, for example, a Si semiconductor substrate, and is provided such that a PN junction surface extending parallel to the front and rear surfaces of the chip terminates on the surface.
[0012]
On the other hand, the first lead electrode 4 and the second lead electrode 5 are formed of, for example, an Fe alloy and, as shown in a plan view in FIG. 2, include a first light emitting element mounting island 4a and a pad 4b adjacent thereto. The lead electrode 4 includes a light receiving element mounting island 5a and a second lead electrode 5 including a pad 5b adjacent thereto. Here, the first lead electrode 4 and the second lead electrode 5 have inner lead portions that are sealed with a translucent resin 6 or an opaque resin 7. These inner lead portions are bent so that the joint surface 2a of the light emitting element 2 mounted on each island 4a is positioned higher than the upper surface 3a of the light receiving element 3.
[0013]
The light-emitting element 2 and the light-receiving element 3 are electrically connected to the first lead island 4a and the second lead island 5a via the conductive bonding agent on the back surface electrode, respectively, and on the front electrode via the Au wire. It is electrically connected to adjacent pads 4b and 5b, respectively.
The light-emitting element 2 and the light-receiving element 3 are integrally sealed with a light-transmitting resin 6 in a state where the light-emitting element 2 and the light-receiving element 3 are electrically connected to the first and second lead electrodes 4 and 5 as described above. The resin 6 and the lead electrodes 4 and 5 protruding therefrom are sealed with a light-impermeable resin 7.
[0014]
Since the photocoupler of the present invention is configured as described above, the photocoupler according to the present invention is approximately two-thirds thinner in the height direction than when a similar light emitting and receiving element is used in the conventional structure. Can do. A part of the high-intensity light emitted from the bonding surface of the light-emitting element and its vicinity is the upper surface of the light-receiving element at the interface including the inclined surface 7a of the light-transmitting resin 6 and the light-impermeable resin 7 shown in FIG. Reflected toward 3a. In this case, it is also understood that there is a light portion that is reflected a plurality of times and indirectly enters the light receiving element 3.
[0015]
Next, the manufacturing method of the photocoupler of this invention is demonstrated.
The photocoupler of the present invention is manufactured using a long lead frame including first and second lead electrodes 4 and 5 as shown in FIG. As shown in FIG. 3A, the lead frame is provided in advance in the lead electrode portion in the vicinity of the island 4a on the light emitting element side so that the bonding surface of the light emitting element is provided at a position higher than the upper surface of the light receiving element. Further, a step 4c due to bending is provided. The lead frame is provided with a connecting bar 8 extending in parallel with the lead electrode portion.
[0016]
As shown in FIG. 3 (b), the light receiving element 2 and the light emitting element 3 are electrically connected to the islands 4a and 5a of the lead frame using adhesives (not shown) such as silver paste, as shown in FIG. While being fixed in a connected state, it is electrically connected to adjacent pads 4b and 5b via Au wires. By mounting the light emitting element 2 and the light receiving element 3 as described above, the light emitting element 2 is aligned so that the joint surface thereof is higher than the upper surface of the light receiving element 3.
[0017]
Next, as shown in FIG. 3 (c), a translucent resin is injected into the cavity between the two molds with the lead frame having the elements 2 and 3 mounted on the upper and lower molds. And by cooling this, the primary mold body in which the elements 2 and 3 are sealed with the translucent resin 6 is formed.
Next, the formed primary mold body is further separated from the non-translucent resin 7 so as to cover the translucent resin body as shown in FIG. A secondary mold body is obtained by applying the sealing. The secondary mold body formed in this way can be easily mass-produced by using the above-described long lead frame.
[0018]
When the secondary mold body is formed in this way, the photocoupler of the present invention shown in FIG. 1 is manufactured by bending and cutting the lead electrode portion by cutting and cutting the connecting bar 8.
FIG. 4 shows a partially enlarged plane of another embodiment of the present invention.
This embodiment is configured in the same manner as the above-described embodiment except that the LED element 2 'is rotated by a certain angle, for example, 45 degrees, and fixed on the island 4a' with respect to the above-described embodiment. .
[0019]
By providing such a LED element 2 ', it is possible to effectively emit light toward the phototransistor (not shown). Incidentally, when the above-described configuration, the side of the generated light is the Photo-coupler, i.e. 1 in the direction perpendicular to the paper surface, but would also be relatively strong radiation, these side It is desirable to provide a reflective surface similar to the reflective surface 7a on the side so as to reflect in the upper direction of the phototransistor.
[0020]
【The invention's effect】
As described in detail above, according to the electronic device package mounting method of the present invention, the package main body having an internal space defined by the concave portion having the internal electrode formed on the surface thereof, and attachable to the package main body. A formed lid body and an electronic element having a first connection body formed on the surface thereof are prepared, the electronic element is attached to the lid body on the back surface, and the lid body is interposed via the second connection body. And then mounting the electronic element to the internal electrode via the first connection body and fixing the lid body to the package body via the second connection body. Thus, a package body with more reliable electrical connection can be obtained.
[0021]
For this reason, in the method of the present invention, it is possible to obtain a package body to which more reliable electrical connection is performed by a simpler process.
The package mounting method of the present invention is configured such that the second connection body is composed mainly of the same material as the first connection body, and the connection via the first connection body and the fixing via the second connection body are performed in the same process. it can.
[0022]
By comprising in this way, the connection by a 1st connection body and the fixation by a 2nd connection body can be performed simultaneously.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a photocoupler of the present invention.
FIG. 2 is a plan view of a lead frame used for manufacturing the photocoupler of the present invention.
FIG. 3 is a diagram showing main manufacturing steps of the photocoupler of the present invention.
FIG. 4 is a plan view showing another embodiment of the present invention.
FIG. 5 is a cross-sectional view of a conventional photocoupler.
[Explanation of symbols]
2 Light-Emitting Element 2a Joint Surface 3 Light-Receiving Element 3a Light-Receiving Surface 4 First Lead Electrode 4a Stepped Part 5 Second Lead Electrode 6 Translucent Resin Body 7 Translucent Resin Body

Claims (3)

A light emitting element having a junction surface terminating on a side surface; a light receiving element having a light receiving surface on an upper surface ; a first lead electrode having a first island electrically connected to the light emitting element; A second lead electrode having a second island opposed to the first island, a translucent resin that seals the light emitting element and the light receiving element in common, and covering the translucent resin An opaque resin for sealing,
The light emitting element has a bonding surface higher than the upper surface of the light receiving element, and one diagonal extension line of the light emitting element extending toward the second island is parallel to the first lead electrode. A photocoupler characterized in that the photocoupler is fixedly disposed on the photocoupler. The interface between the translucent resin and the non-translucent resin is formed in a shape that reflects light emitted from the light emitting element in a direction extending to the joint surface thereof directly to the upper surface of the light receiving element. The photocoupler described in 1. A light-emitting element having a junction surface terminating on a side surface, a light-receiving element having a light-receiving surface on an upper surface, a first island for mounting the light-emitting element, and lower than the first island, provided opposite to the first island. Preparing a lead frame provided with a second island for mounting the light receiving element ;
The light emitting element and the light receiving element are respectively disposed on the first and second islands such that one diagonal extension line of the light emitting element extending toward the second island is orthogonal to one side of the first island. A process of placing ;
A step of integrally sealing the light emitting element and the light receiving element with a translucent resin ;
A method for producing a photocoupler, comprising a step of sealing with a non-translucent resin so as to cover the translucent resin.

Images