JP4761766B2 - Optical coupling element and electronic device using the same - Google Patents

Description

  The present invention relates to an optical coupling element composed of a light emitting element and a light receiving element arranged on the same plane, and an electronic apparatus using the same.

  As described in Patent Document 1, the conventional optical coupling element is configured so that the light emitting element and the light receiving element are vertically opposed to each other. FIG. It is sectional drawing which showed the structure of the element. In FIG. 4, in the conventional optical coupling element, two L-shaped metal lead frames 13a and 13b and two L-shaped and similar metal lead frames 13c and 13d are formed. Are arranged on the left and right respectively. Among these, the light emitting element 11 is provided in a recess in the lower surface of the tip portion bent upward in the lead frame 13a arranged on the left. The light receiving element 12 is provided on the upper surface of the tip portion bent downward in the lead frame 13c arranged on the right. The light emitting element 11 and the light receiving element 12 face each other as described above, and the light emitted from the light emitting element 11 is received by the light receiving element 12.

  Among these, the bottom electrode 11b is provided on the bottom surface of the light emitting element 11 disposed downward, and the bottom electrode 11b is connected to the lead frame 13a by being bonded to the bottom surface of the leading end of the lead frame 13a. Has been. Further, a surface electrode 11a is provided on the surface of the light emitting element 11, and the surface electrode 11a is connected to the tip of a lead frame 13b disposed on the left side together with the lead frame 14a by a wire 14a. The light emitting element 11 is precoated with a transparent silicon resin, and a precoat 15 is formed around the light emitting element 11.

  A bottom electrode 12b is provided on the bottom surface of the light receiving element 12 arranged upward, and the bottom electrode 12b is connected to the lead frame 13c by bonding to the top surface of the tip of the lead frame 13c. . Further, a surface electrode 12a is provided on the surface of the light receiving element 12, and the surface electrode 12a is connected to the tip of a lead frame 13d disposed on the right side together with the lead frame 13c by a wire 14b.

Further, the periphery of the lead frame 13a provided with the light emitting element 11 and the tip part of the lead frame 13c provided with the light receiving element 12 are guided around the periphery thereof. Molded with a resin having As the resin having the light guiding property, generally, a translucent resin 16 that can be easily molded is used. The periphery of the transparent resin mold is further molded with an opaque resin 17.
JP 09-129914 A

  In the above-described conventional optical coupling element, the light emitting element 11 and the light receiving element 12 are disposed on the metal lead frame 13a and the lead frame 13c, respectively. There is a problem that the attracted noise is easily received from the bottom surface of the light emitting element 11 and the light receiving element 12 by the metal lead frame. In particular, a light receiving element constituted by a phototriac has a problem that erroneous firing is likely to occur due to these noises when light reception is turned off.

  In addition, a semi-transparent resin 16 that is easy to mold is used to mold the light-emitting element 11 and the light-receiving element 12, but the translucent resin increases the transmission efficiency of light emitted from the light-emitting element to the light-receiving element. There was a problem of being bad.

  Further, in the above-described conventional optical coupling element, since the light emitting element 11 and the light receiving element 12 are arranged vertically, there is a problem that the package of the optical coupling element becomes thick.

  Therefore, the present invention has been made to solve the above-described problems. Compared to the conventional example, the present invention is less susceptible to external noise from the bottom surface of the light emitting element and the light receiving element, and from the light emitting element to the light receiving element. It is an object of the present invention to provide an optical coupling element having a high light transmission efficiency and a thin package.

  The optical coupling element of the present invention is an optical coupling element composed of a light emitting element and a light receiving element arranged on the left and right on the same plane, and the light emitting element and the light receiving element are arranged on the left and right sides of the light guide having insulation properties. The bottom surface of the light emitting element and the bottom surface of the light receiving element are bonded to the top surface of the light guide, and the light guide is mounted on the top surface of the main frame. Each electrode provided in the light receiving element is connected to a separate lead frame.

  According to the above optical coupling element, since the light emitting element and the light receiving element are mounted on the insulating light guide, it is possible to make it difficult for external noise to be received from the bottom surface of the light emitting element and the light receiving element. . Moreover, the light emitting element and the light receiving element are mounted on the same light guide, and the bottom surface of the light emitting element and the bottom surface of the light receiving element are bonded to the top surface of the light guide. Therefore, the light emitted from the light emitting element is easily transmitted to the light receiving element via the light guide. When the electrode is not formed on the bottom surface of the light emitting element or the light receiving element, the light emitted from the light emitting element is efficiently incident on the light guide from the bonded portion between the bottom surface of the light emitting element and the top surface of the light guide. In addition, the light that has passed through the light guide can be efficiently incident on the light receiving element from the bonding portion between the bottom surface of the light receiving element and the top surface of the light guide. Therefore, the light transmission efficiency from the light emitting element to the light receiving element can be improved. Further, since the light emitting element and the light receiving element are arranged on the same plane, the thickness of the optical coupling element package can be reduced.

  In the above optical coupling element, the main frame is composed of a left frame and a right frame disposed on the left and right on the same plane, and between the opposite end of the left frame and the end of the right frame. A light guide may be installed. Since the frame is generally formed of a metal, the conductor portion such as the main frame and the lead frame can be completely separated between the light emitting element side and the light receiving element side by doing in this way. The pressure resistance test of the product can be performed smoothly.

  In the above optical coupling element, in the optical coupling element in which at least one electrode is formed on the surface of the light emitting element, the light receiving element, or both, the electrode and the lead frame are connected by a wire. It is reasonable. In addition, in the optical coupling element in which at least one electrode is formed on the bottom surface of the light emitting element, the light receiving element, or both of them, a connection electrode in contact with the electrode is formed on the light guide, and the connection electrode and the lead It is reasonable to connect the frame to the wire.

  Further, in the above optical coupling element, the light guide has a convex portion in which the central portion of the light guide projects upward, and the convex portion is inserted between the light emitting element and the light receiving element. May be. By doing in this way, the light which the light emitting element light-emitted also injects also into the convex part of a light guide, and the transmission efficiency of the light from a light emitting element to a light receiving element can be improved further.

  Further, in the above optical coupling element, the light emitting element, the light receiving element, or both of them are sealed on the light guide with a transparent precoat material, and by this sealing, a part of the precoat material is formed. It is preferable to adhere to the light guide. Here, sealing on the light guide with the precoat material means that the light emitting element and the light receiving element placed on the light guide are placed around each element in a state where each of these elements is placed. Coating is performed using a precoat material including the surface of the light guide.

  By doing in this way, a light emitting element and a light receiving element can be protected. In particular, when a light-emitting diode is used as the light-emitting element, the semiconductor junction that emits light is exposed, which is preferable. In addition, since the light emitting element and the light receiving element are sealed on the light guide by a precoat material having transparency, the light emitted from the light emitting element is incident on the precoat material around the light emitting element and the precoat material. It becomes easy for the light incident on the light to enter the light guide from the precoat material. In addition, the light that has passed through the light guide is incident on the precoat material around the light receiving element and can easily reach the light receiving element. Therefore, the transmission efficiency of light from the light emitting element to the light receiving element can be further improved.

  In the above case, the light guide has a convex portion formed by projecting the central portion of the light guide upward, and the convex portion is inserted between the light emitting element and the light receiving element. It is preferable that a part of the precoat material is adhered to the convex portion. By doing in this way, the light incident on the precoat material enters the convex portion of the light guide from the precoat material, and the light that has passed through the convex portion of the light guide enters the precoat material around the light receiving element. Therefore, it becomes easy to reach the light receiving element. Therefore, the light transmission efficiency from the light emitting element to the light receiving element can be further improved.

  In addition, the above optical coupling element can be used in various electronic devices. In the electronic apparatus using the above optical coupling element, the above-described functions and effects are applied as they are.

  According to the optical coupling element of the present invention, since the light emitting element and the light receiving element are mounted on the light guide having insulating properties, it is difficult to receive external noise from the bottom surface of the light emitting element or the light receiving element. it can. In addition, since the light emitting element and the light receiving element are mounted on the same light guide, light emitted from the light emitting element is transmitted to the light receiving element through the light guide, so that light is transmitted from the light emitting element to the light receiving element. Efficiency can be improved. Further, since the light emitting element and the light receiving element are arranged on the same plane, the thickness of the package can be reduced.

  In addition, a main frame generally made of metal is composed of a left frame and a right frame arranged on the same plane on the left and right sides, and the leading end of the left frame and the leading end of the right frame facing each other. Since the structure has an insulating light guide interposed between them, the conductor parts such as the main frame and the lead frame can be completely separated between the light emitting element side and the light receiving element side, The pressure resistance test of the coupling element product can be performed smoothly.

  Further, the light guide has a convex portion in which the central portion of the light guide projects upward, and the convex portion is inserted between the light emitting element and the light receiving element, so that the light emitting element emits light. When light enters the convex portion of the light guide, the light transmission efficiency from the light emitting element to the light receiving element can be further improved.

  Hereinafter, the optical coupling element in the present embodiment will be described in detail with reference to the drawings.

<Embodiment 1>
FIG. 1 is a front view showing a state before molding of the optical coupling element according to Embodiment 1, and a portion indicated by a two-dot chain line shows an outer shape after molding. FIG. 2 is a plan view showing the main part of the optical coupling element in the first embodiment.

  In the optical coupling element according to the first embodiment, in FIGS. 1 and 2, a metal left frame 4 a having an L shape in front view and an L shape symmetric to the left frame 4 a and the same metal right frame 4 b are provided. The left frame 4a and the right frame 4b constitute a main frame 4 that is opposed to the left and right. The horizontal portion of the left frame 4a and the horizontal portion of the right frame 4b are opposed to each other, and the leading end of the horizontal portion of the left frame 4a and the leading end of the horizontal portion of the right frame 4b are in the forward direction, respectively. And it protrudes horizontally in the rear direction and is formed in a planar view shape.

  A plate-like rectangular light guide 3 in plan view is provided between the square tip of the left frame 4a and the square tip of the right frame 4b. Both end portions are mounted on the front end portion of the left frame 4a and on the front end portion of the right frame 4b, respectively. The light guide 3 is made of transparent glass or transparent ceramic, has electrical insulation, and can efficiently enter and transmit light.

  The light emitting element 1 is mounted on the upper surface of the left end portion of the light guide 3 by die bonding, and the light receiving element 2 is mounted by die bonding on the upper surface of the right end portion. The light emitting element 1 is a light emitting diode having a semiconductor junction that emits light formed of gallium and arsenic. The light receiving element 2 is a phototransistor or a phototriac.

  The light emitting element 1 mounted on the upper surface of the light guide 3 includes two electrodes, an anode and a cathode. In the light emitting element 1 according to the first embodiment, the surface electrode 1a which is one of the electrodes is the light emitting element 1. The bottom electrode 1b, which is the other electrode, is formed on the bottom surface of the light emitting element 1, respectively.

  The light guide 3 on which the light emitting element 1 is mounted is made of a metal having the same L shape as the left frame 4a, in front of and behind the left frame 4a on which the light guide element 3 is further mounted, in parallel with the left frame 4a. Two lead frames 6a and 6b are provided. The leading end portions of these lead frames 6a and 6b are bent at a substantially right angle inward in the horizontal direction to form protrusions that face in the front-rear direction with the left frame 4a interposed therebetween. And this protrusion part of the lead frame 6a and the surface electrode 1a formed in the surface of the light emitting element 1 are connected by the electroconductive wire 7a which used the gold wire etc. Further, a connection electrode 5 is formed on the surface of the light guide 3 that is in contact with the bottom electrode 1b formed on the bottom surface of the light emitting element 1, and is in contact with and electrically connected to the bottom electrode 1b. The lead portion 5 and the protrusion at the tip of the lead frame 6b are connected by a conductive wire 7b using a gold wire or the like.

  The light receiving element 2 mounted on the upper surface of the light guide 3 also includes two electrodes, an anode and a cathode, both of which are formed on the surface of the light receiving element 2.

  In the same manner as the light emitting element 1, the light guide 3 on which the light receiving element 2 is mounted is placed in front of and behind the right frame 4b on which the light receiving element 2 is further mounted, in parallel with the right frame 4b. Two lead frames 6c and 6d made of metal and having the same L shape as the frame 4b are provided. The leading end portions of these lead frames 6c and 6d are each bent at a substantially right angle inward in the horizontal direction to form protrusions that face in the front-rear direction with the right frame 4b interposed therebetween. And this protrusion part of the lead frame 6c and one surface electrode 2a formed on the surface of the light receiving element 2 are connected by a conductive wire 7c using a gold wire or the like, and the lead frame 6d The protrusion and the other surface electrode 2b formed on the surface of the light receiving element 2 are connected by a conductive wire 7d using a gold wire or the like.

  The light-emitting element 1 and the light-receiving element 2 mounted on both ends of the light guide 3 are sealed on the light guide by transparent precoat materials 8a and 8b, such as silicon resin. . That is, the light-emitting element 1 and the light-receiving element 2 placed on the light guide 3 have the light guide body surface around the elements 1 and 2 in a state where these elements 1 and 2 are placed. In addition, it is coated using precoat materials 8a and 8b.

  In addition, the periphery of the distal ends of the left and right frames 4a and 4b and the distal ends of the lead frames 6a, 6b, 6c and 6c in the optical coupling element having the above-described structure is further molded with an opaque resin 9.

  As can be seen from the above description, in the above optical coupling element, the left frame 4a and the lead frames 6a and 6b are provided on the left side, and the right frame 4b and the lead frames 6c and 6d are provided on the right side. Frame is provided. Of these, only four lead frames 6a and 6b and lead frames 6c and 6d are used for electrical connection with an external electric circuit or the like. Therefore, the left frame 4a and the right / right frame 4b are cut at a portion exposed to the outside of the mold formed of the opaque resin 9.

  The operation of the optical coupling element configured as described above is as follows. That is, when an input signal is input to the light emitting element 1 via the lead frame 6a and the lead frame 6b, the light emitting element 1 emits light. The light emitted from the light emitting element 1 is incident on the precoat material 8a around the light emitting element 1, and the light incident on the precoat material 8a is further bonded to the precoat material 8a and the light guide 3 Then, the light enters the light guide 3. Further, the light that has passed through the light guide 3 passes through the portion where the light guide 3 and the precoat material 8 b are bonded, enters the precoat material 8 b around the light receiving element 2, and reaches the light receiving element 2. Is received. An output signal is output from the light receiving element 2 through the lead frame 6c and the lead frame 6d.

  In the above optical coupling element, both of the two electrodes of the light receiving element 2 are formed on the surface of the light receiving element 2, but when one electrode of the light receiving element is formed on the bottom surface, the above light emitting element 1, a connection electrode is formed on the surface of the light guide 3, and the lead portion of the connection electrode and the protrusion at the tip of the lead frame are connected by a conductive wire using a gold wire or the like. do it. In addition, when the two electrodes of the light emitting element are both formed on the surface of the light emitting element, the two electrodes and the protrusions at the tip end portions of the respective lead frames are made of gold as in the light receiving element 2 described above. What is necessary is just to connect with the electroconductive wire which used the wire | line etc.

  Further, in the above optical coupling element, the main frame 4 made of metal is composed of the left frame 4a and the right frame 4b arranged on the left and right on the same plane, and the left frame 4a facing each other. An insulating light guide 3 is installed between the tip and the tip of the right frame 4b. However, as a structure of the optical coupling element, the main frame 4 may be integrally formed by coupling the tip of the left frame 4a and the tip of the right frame 4b.

  As described above, the main frame 4 made of metal is divided into the left frame 4a and the right frame 4b that are arranged on the left and right on the same plane. Can be completely separated into the light emitting element 1 side and the light receiving element 2 side, that is, electrically on the primary side (input side) and secondary side (output side). It is. By doing in this way, when conducting an electrical withstand voltage test between the primary side and the secondary side for the product of the above optical coupling element, no special consideration is required. This is because the pressure resistance test of the product of the optical coupling element can be performed smoothly.

  According to the optical coupling element in the first embodiment, since the light emitting element 1 and the light receiving element 2 are mounted on the light guide 3 having insulating properties, noise from the outside is eliminated by the light emitting element 1 and the light receiving element. 2 can be made difficult to receive from the bottom surface. Further, the light emitting element 1 and the light receiving element 2 are mounted on the same light guide 3, and the bottom surface of the light emitting element 1 and the bottom surface of the light receiving element 2 are bonded to the top surface of the light guide 3. Therefore, the light emitted from the light emitting element 1 is easily transmitted to the light receiving element 2 through the light guide 3. When no electrode is formed on the bottom surface of the light emitting element 1 or the light receiving element 2, in particular, the light emitted from the light emitting element 1 is guided from the bonded portion between the bottom surface of the light emitting element 1 and the top surface of the light guide 3. 3 and the light that has passed through the light guide 3 can be efficiently incident on the light receiving element 2 from the bonded portion between the bottom surface of the light receiving element 2 and the top surface of the light guide 3. Therefore, the light transmission efficiency from the light emitting element 1 to the light receiving element 2 can be improved. Moreover, since the light emitting element 1 and the light receiving element 2 are arranged on the same plane, the thickness of the optical coupling element package can be reduced.

  Moreover, since the light emitting element 1 and the light receiving element 2 are sealed on the light guide 3 by the precoat materials 8a and 8b having transparency, the light emitting element 1 and the light receiving element 2 can be protected. In particular, when a light emitting diode is used as the light emitting element 1, the semiconductor junction that emits light is exposed, which is preferable. The light-emitting element 1 and the light-receiving element 2 are sealed on the light guide 3 with transparent precoat materials 8 a and 8 b, and part of the precoat materials 8 a and 8 b are bonded to the light guide 3. Therefore, the light emitted from the light emitting element 1 enters the precoat material 8a around the light emitting element 1, and the light incident on the precoat material 8a easily enters the light guide 3 from the precoat material 8a. Further, the light that has passed through the light guide 3 enters the precoat material 8 b around the light receiving element 2 and easily reaches the light receiving element 2. Therefore, the light transmission efficiency from the light emitting element 1 to the light receiving element 2 can be further improved.

<Embodiment 2>
FIG. 3 is a front view showing a state of the optical coupling element according to the second embodiment before molding, and a portion indicated by a two-dot chain line shows an outer shape after molding.

  The structure of the optical coupling element in the second embodiment is almost the same as the optical coupling element in the first embodiment. The difference is that the light guide 3 is formed such that the central portion of the light guide 3 protrudes upward. The convex portion 3a is inserted between the light emitting element 1 and the light receiving element 2, and part of the precoat materials 8a and 8b is bonded to the convex portion 3a. Is a point.

  Therefore, according to the optical coupling element in the second embodiment, in addition to the same operations and effects as the optical coupling element in the first embodiment described above, the following operations and effects are provided. That is, as described above, the convex portion 3a of the light guide 3 is inserted between the light emitting element 1 and the light receiving element 2, and the light emitted from the light emitting element 1 is projected to the convex portion 3a of the light guide 3. Therefore, the light transmission efficiency from the light emitting element 1 to the light receiving element 2 can be further improved.

  In addition, since a part of the precoat material is adhered to the convex portion, the light incident on the precoat material 8a around the light emitting element 1 enters the convex portion 3a of the light guide 3 from the precoat material 8a and is guided. Since the light that has passed through the convex portion 3 a of the light body 3 enters the precoat material 8 b around the light receiving element 2, the light can easily reach the light receiving element 2. Therefore, the light transmission efficiency from the light emitting element 1 to the light receiving element 2 can be further improved.

FIG. 3 is a front view showing a state before the optical coupling element is molded in the first embodiment. FIG. 3 is a plan view showing a state before molding a main part of the optical coupling element in the first embodiment. FIG. 10 is a front view showing a state before the optical coupling element is molded in the second embodiment. It is sectional drawing which showed the structure of the optical coupling element of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting element 1a Surface electrode 1b Bottom electrode 2 Light receiving element 2a Surface electrode 2b Surface electrode 3 Light guide 3a Protrusion part 4 Main frame 4a Left frame 4b Right frame 5 Connection electrode 6a Lead frame 6b Lead frame 6c Lead frame 6d Lead frame 7a Wire 7b Wire 7c Wire 7d Wire 8a Precoat material 8b Precoat material 9 Opaque resin 11 Light emitting element 11a Surface electrode 11b Bottom electrode 12 Light receiving element 12a Surface electrode 12b Bottom electrode 13a Lead frame 13b Lead frame 13c Lead frame 13d Lead frame 14a Wire 14a Wire 15 Pre-coating 16 Translucent resin 17 Opaque resin

Claims (5)

An optical coupling element composed of a light emitting element and a light receiving element arranged on the left and right on the same plane,
The light emitting element and the light receiving element are respectively mounted on left and right ends of an insulating light guide, and the bottom surface of the light emitting element and the bottom surface of the light receiving element are bonded to the top surface of the light guide. As well as
The light guide is mounted on the upper surface of the main frame;
Each electrode provided in the light emitting element and the light receiving element is connected to a separate lead frame ,
The light emitting element, the light receiving element, or both are sealed on the light guide by a precoat material having transparency,
The light guide includes a convex portion in which a central portion of the light guide projects upward, the convex portion is inserted between the light emitting element and the light receiving element, and the precoat material A part of the optical coupling element is bonded to the convex part .   The main frame is composed of a left frame and a right frame arranged on the left and right on the same plane, and the light guide is provided between a front end portion of the left frame and a front end portion of the right frame facing each other. The optical coupling element according to claim 1, wherein the body is constructed.   3. The light according to claim 1, wherein at least one of the electrodes is formed on a surface of the light emitting element, the light receiving element, or both, and the electrode and the lead frame are connected by a wire. Coupling element.   At least one of the electrodes is formed on the bottom surface of the light emitting element, the light receiving element, or both, and a connection electrode in contact with the electrode is formed on the light guide, and the connection electrode The optical coupling element according to claim 1, wherein the lead frame is connected with a wire. An electronic device in which the optical coupling element according to any one of claims 1 to 4 is used.

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