JP2000340828A - Photocoupler and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photocoupler which has a light emitting device and a photodetector, enables size reduction and cost reduction, and further, is easy to manufacture. SOLUTION: Electrodes 14, 16, 17 and 19 with prescribed shapes are formed on a printed wiring board 11. A light emitting device 12 and a photodetector 13 are mounted on the electrodes 14 and 17 respectively. The light emitting device 12 is connected to the electrode 16 with a conductor 15, and the photodetector 13 is connected to the electrode 19 with a conductor 18. The light emitting device 12, the photodetector 13 and the conductors 15 and 18 are contained in a rectangular parallelpiped package 20, made of a transparent material and a light shielding cover is put on the package 20 with an air gap therebetween.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocoupler for transmitting a signal using light as a medium without using an electrical connection, and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG. 13 shows a conventional photocoupler, 1 is a lead frame on which a light emitting element 3 such as an LED is mounted, and 2 is a conductive line from the light emitting element 3. 5 is a lead frame for connecting the reference frame No. 5. Reference numeral 6 denotes a lead frame on which a light receiving element 8 such as a phototransistor is mounted, and reference numeral 7 denotes a lead frame for connecting a conductive line 9 from the light receiving element 8. The lead frame 1 and the lead frame 2 are connected by a typer 35. The lead frame 6 and the lead frame 7 are connected by a typer 36.

The above-mentioned lead frame 1 and lead frame 6
Makes the mounted light emitting element 3 and light receiving element 8 face each other,
The package is fixed by a package 39 formed of an opaque material in a rectangular parallelepiped. The inside of the package 39 is filled with a transparent material 37.

The typer 35 and the typer 36 are cut and removed with the lead frames 1, 2, 6, and 7 fixed by the package 39. These lead frames 1, 2, 6, and 7 are bent outward at the leading end so as to match the bottom surface of the package 39, as shown in FIG.

[0005]

The above photocoupler has the following problems. First, since the lead frames 1, 2, 6, and 7 provided in the photocoupler are manufactured by a method such as etching, the cost is high, and it is difficult to reduce the apparatus price. . Further, the lead frame 1 on which the light emitting element 3 is mounted and the lead frame 6 on which the light receiving element 8 is mounted are fixed by a package 39 so as to keep a predetermined interval. Therefore, mounting the lead frames 1 and 6 requires precise jigs and tools and forming dies. In addition, since the distance between the light emitting element 3 and the light receiving element 4 tends to vary in each product, it is difficult to make the signal transmission efficiency constant,
Products with guaranteed quality may not be available.

Further, since the overhanging bases of the lead frames 1, 2, 6, and 7 are located above the lower surface of the package 39, when the photocoupler is mounted on the mounting substrate, the lead frames are not used. A step of bending and forming the pieces 1, 2, 6, and 7 so as to contact the mounting board is required. Therefore, it is difficult to downsize the photocoupler described above because the lead frames 1, 2, 6, and 7 are used.

[0007]

SUMMARY OF THE INVENTION The present invention provides a photocoupler.
-Intended to solve the above problems
As a first invention, a copper foil portion having a predetermined shape is provided as an electrode.
Light-emitting element and light-receiving element at predetermined positions on the copper foil
Element, and the light emitting element and the light receiving element are
Placed inside the package and outside the package
The outer shape of the cross section including the light emitting element and the light receiving element
It is almost parallel to the line connecting the optical
The distance D between the midpoint of the optical element and the outline is
The distance from the element is L, and the total refraction between the package and its out-of-plane
When the rate is N, D ≦ (L / 2) (N²-1)^1/2  And the package has a light
Characterized by having a light-shielding cover with a logical interval.
A photocoupler is proposed.

The photocoupler thus configured does not have an expensive lead frame, so that it is easy to reduce the cost, the manufacturing process is simplified, and mass production is facilitated. Further, since the structure is simple, it is easy to reduce the size, which is advantageous for assembling to an electronic circuit device. Furthermore, there is no unstable element in the structure, and the quality during mass production is stable.

According to a second aspect of the present invention, a light emitting element and a light receiving element are provided at predetermined positions of the copper foil part of a wiring board having a copper foil part of a predetermined shape as an electrode. A photocoupler characterized by providing holes in the wiring board is proposed. In the photocoupler configured as described above, even if the light emitting element and the light receiving element are far apart from each other, the light of the light emitting element enters the light receiving element, so that the withstand voltage can be increased.

According to a third aspect of the invention, a light emitting element and a light receiving element are provided at predetermined positions of the copper foil part of a wiring board having a copper foil part of a predetermined shape as an electrode, and the light emitting element and the light receiving element are made of a transparent material. A photocoupler is proposed, wherein the photocoupler is provided inside a package and a reflection material is provided on the outer surface of the package. Photocoupler configured as above
It is not necessary to provide a light-shielding cover, and there is no dimensional restriction, so that it is possible to reduce the size in any shape.

According to a fourth aspect of the present invention, there is provided a wiring board in which a first electrode for mounting a light receiving element and a second electrode for mounting a light emitting element are arranged in a matrix, respectively. The light receiving element and the light emitting element are mounted on the electrodes, respectively, and the lead line connecting terminals of the light receiving element and the light emitting element are connected to predetermined electrodes formed on the wiring board with the lead lines.
A package is formed on a wiring board, the light-receiving element and the light-emitting element are arranged inside a transparent material package, and a reflection material is provided on an outer surface of the package. A manufacturing method is proposed in which a plurality of photocouplers each having a set of the light receiving element and the light emitting element are manufactured by cutting a position.

[0012]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway perspective view of a photocoupler according to a first embodiment. A wiring board 11 includes a light emitting element 12 such as an LED and a light receiving element 13 such as a phototransistor. The wiring board 11 has an electrode 14 for mounting the light emitting element 12 and a light emitting element 1.
An electrode 16 for connecting the conductive line 15 from the second element 2, an electrode 17 for mounting the light receiving element 13, and an electrode 19 for connecting the conductive line 18 from the light receiving element 13 are provided in predetermined shapes, respectively. I have.

Reference numeral 20 denotes a transparent material formed in a rectangular shape.
This is a package made of a transparent material formed in a rectangular shape so that the light emitting element 12 and the light receiving element 13 are embedded. Reference numeral 21 denotes a light-shielding cover for shielding external light from the light-receiving element 13, and an optical gap 2 between the light-receiving element 13 and the package 20.
2 are provided.

FIG. 2 is a vertical side view of the photocoupler. In this figure, the light of the light emitting element 12 is transmitted to a package 20 located immediately above the intermediate point between the light emitting element 12 and the light receiving element 13.
At the point A, and enters the light receiving element 13. Light emitting element 12
The condition for total reflection of light from the point A is that the total refractive index of the transparent material used for the package 20 and its out-of-plane refractive index is N, and the point A
Is represented by the following equation, where θ is the incident angle of light at However,
The out-of-plane is air outside the plane of the package 20. N · Sin θ ≧ 1 (1)

Here, if the distance between the light emitting element 12 and the light receiving element 13 is L, and the distance between the line connecting the light emitting element 12 and the light receiving element 13 and the point A is D, the point A of the light from the light emitting element 12 is obtained.
Sin θ can be expressed by the following equation, where θ is the incident angle at. Sin θ = (L / 2) (L ² + D ² ) ^−1/2 (2) From the above equations (1) and (2), the light from the light emitting element 12 is point A.
The condition of the above D for total reflection at is as follows. D ≦ (L / 2) (N ² −1) ^1/2 ... (3)

The above condition is when the point A of the package 20 is in contact with air. Therefore, a gap 22 is provided between the light-shielding cover 21 and the package 20. Also,
The point A of the package 20 is other than air (package 2
0), the refractive index of the contacting material is m, the refractive index of the transparent material of the package 20 is p, and the total refractive index N = p / m. The condition of the above D can be obtained. However, p> m. Under such conditions, the inside of the space 22 may be formed.

FIG. 3 is a partially cutaway perspective view of a photocoupler according to a second embodiment. In this figure, reference numeral 11 denotes the same wiring board as the wiring board 11 shown in FIG. Reference numeral 31 denotes a transparent material package in which the light emitting element 12 and the light receiving element 13 are embedded and formed in a semi-cylindrical shape. The outer shape of the package 31 is a semi-cylindrical shape having a radius r with the center line C connecting the light emitting element 12 and the light receiving element 13 as a center line, and the value of r is the value of D determined by the above equation (3). Used. Reference numeral 32 denotes a light shielding cover for shielding the light receiving element 13 from external light.
A gap 3 is provided between the light shielding cover 32 and the package 31.
3 are provided.

The photocoupler configured as described above reflects light from the light emitting element 12 at an arcuate line B indicated by the cross-sectional outline of the package 31 and enters the light receiving element 13. For this reason, the photocoupler having the above-described configuration can transmit more reflected light to the light receiving element 1 than the photocoupler shown in FIG.
3 can be incident. Therefore, the ratio (transmission efficiency) between the output signal and the input signal can be increased.

FIG. 4 shows a photocoupler according to a third embodiment.
3 is a partially cutaway perspective view of FIG. This photocoupler has a configuration in which the withstand voltage between the input terminal (light emitting element side) and the output terminal (light receiving element side) is increased. In this figure, 41
Is a wiring board for providing the light emitting element 12 and the light receiving element 13. The wiring board 41 has an electrode 44 for mounting the light emitting element 12, an electrode 46 for connecting a conductive line 45 from the light emitting element 12, An electrode 47 for mounting the light receiving element 13 and an electrode 49 for connecting a conductive line 48 from the light receiving element 13 are provided in predetermined shapes, respectively. Further, the distance between the light emitting element 12 and the light receiving element 13 is 2L (two times L shown in FIG. 2), and the light emitting element 12 and the light receiving element 1
A square hole 50 is provided between these elements 12 and 13 at a distance L from the element 3.

Reference numeral 51 denotes a transparent material package in which the light emitting element 12 and the light receiving element 13 are embedded and formed in a rectangular shape. 52 is a light shielding cover for shielding the light receiving element 13 from external light. This package 51 and light-shielding cover 5
A gap 53 is provided between the first and second members.

FIG. 5 shows a photocoupler according to a third embodiment.
It is a vertical side view. In this configuration, a gap 53 is provided between the package 51 and the light-shielding cover 52, and a rectangular hole 50 is formed in the wiring board between the light emitting element 12 and the light receiving element 13.
Is provided, the light of the light emitting element 12 is divided into four points C, D, and approximately four between the light emitting element 12 and the light receiving element 13.
The light is totally reflected at E and enters the light receiving element 13. In addition, the light reflected at the point A 'of the package 51 immediately above the point D also enters the light receiving element 13.

With the above configuration, the electrodes 44 and 46 related to the light emitting element 12 and the electrodes 47 and 4 related to the light receiving element 13
9 is wider than that of the wiring board 11 shown in FIG. 1, so that the withstand voltage between the input terminal and the output terminal can be increased. If the package 51 has a semi-cylindrical shape similar to the package 31 shown in FIG. 3, high transmission efficiency can be obtained.

FIG. 6 is a partially cutaway perspective view of a photocoupler according to a fourth embodiment. In this figure, 11 is the same wiring board as the wiring board shown in FIG. Numeral 61 denotes a rectangular transparent material package in which the light emitting element 12 and the light receiving element 13 are embedded.

Reference numeral 62 denotes a reflector provided on the upper surface of the package 61, and the package 61 side is used as a reflection surface 63. The reflecting material 62 can be obtained by depositing aluminum, applying a paint mixed with aluminum powder or magnesium oxide powder, printing with ink, or bonding a mirror-finished metal plate. it can. In the configuration described above, the shape of the package 61 is changed to the package 20, 3
There is no restriction as in 1, and the degree of freedom in design increases. Further, the light-shielding cover for shielding the external light shown in each of the above embodiments may not be particularly provided.

Next, the photocoupler shown in FIG.
A method of manufacturing the device will be described. 7 is a plan view of a rectangular printed wiring board 72, and FIG. 8 is a partially enlarged plan view of the printed wiring board 72. The printed wiring board 72 has a copper foil portion 73 of a predetermined shape. Of the copper foil portions 73, 7
Reference numeral 4 denotes an electrode for mounting the light-emitting element 12, and 75 denotes an electrode for mounting the light-receiving element 13. Each of the electrodes 1 shown in FIG.
4 and 17. Reference numerals 76 and 77 are electrodes to be the electrodes 16 and 19 in FIG.

These electrodes 74, 75, 76, 77 are connected to copper foil portions 78, 79, 80, 81 on the respective external connection terminals 82.
And each connection terminal 82 has a through hole 8.
3 are formed on the rear surface of the substrate 72 and serve as electrical connection portions of the terminals 82 shown in FIG. Reference numeral 84 denotes a conductive portion necessary for performing gold plating on each portion of the copper foil portion 73 formed on the printed wiring board 72.

A large-diameter hole 85 formed on one side of the printed wiring board 72 is a reference hole for use in positioning a machine tool when manufacturing a product. In the following description, the vertical arrangement of the electrodes 74 and the electrodes 75 in FIG. 7 will be described as columns, and the horizontal arrangement of the through-holes 83 will be described as rows.

On the upper surface of the printed wiring board 72 formed as described above, first, as shown in FIG. 10, light shielding frames 92 of a plurality of square windows are formed using a light-shielding resin material. The light-shielding frame 92 is formed such that the mounting part of the light-emitting element 12 of the electrode 74 and the mounting part of the light-receiving element 13 of the electrode 75 are accommodated in the square window of the light-shielding frame 92. In forming the light-shielding frame 92, the resin material is also filled into the holes 86 for preventing the light-shielding frame 92 from falling off to prevent the light-shielding frame 92 from falling off in the subsequent steps.

In FIG. 10, the copper foil 73 and the through-hole 83 formed on the printed wiring board 72 are omitted. After the shading frame 92 is formed, the light emitting element 1
2 and the light receiving element 13 are mounted on predetermined positions of the respective electrodes 74 and 75, and then the upper electrode of the light emitting element 12 is connected to the electrode 76.
The upper electrode of the light receiving element 13 is connected to the electrode 77 by the conductive line 1
5, 18, and (45, 48) are connected. The mounting of the light emitting element 12 and the light receiving element 13 and the conductive wires 15, 1
8, (45, 48) is laid out by a large number of copper foil portions 7 on FIG.
3 is similarly performed for each.

Subsequently, as shown in FIG. 11, a transparent material is filled in the light-shielding frame 92 so as to bury the light-emitting element 12, the light-receiving element 13, and the conductive wires 15 and 18, thereby forming a rectangular parallelepiped shape. Then, a package 94 is formed. FIG. 11 is an enlarged partial sectional view taken along line AA (column direction) in FIG. Next, the reflecting material 9 is provided on the upper surface of the package 94.
5 is sprayed or applied by a method such as printing,
A reflection surface 96 is formed on the package 94 side. Further, a protective layer for protecting the reflective material 95, a colored layer for design, and the like can be further laminated thereon as required.

The photocoupler manufactured as described above is cut into individual photocouplers as follows. In FIG. 7, the printed wiring board 72 is first cut in the column direction of Y1, Y2, Y3,.
Cutting along Yn, followed by X1, X2, X in the row direction
3. Cut along Xn. Thus, the individual photocouplers are formed in the shape shown in FIG.

Here, in comparison with the members shown in FIG. 6, the printed wiring board 72 becomes the individual wiring board 11, the package 94 becomes the package 61, the reflecting material 95 becomes the reflecting material 62, and The through-hole 83 is cut off and the notch 2 is formed.
2, 23, 24, and 25. In addition, FIG.
No component to be compared with No. 2 is described. This shading frame 9
The object 2 is to shield light so as to prevent external light from entering the light receiving element 13. The light emitting element 2 is provided as necessary when implementing the present invention.

That is, the photocoupler is mainly mounted on an electronic circuit board in various electric devices.
Many electric devices are housed in a housing and have a light shielding property.
The mounting place of the electronic circuit board is often in a dark room. Therefore, depending on the environment in which the photocoupler is used, there is no need to shield external light, and the light receiving element strongly reacts to light from the front.
Light is shielded by the light-shielding property of the reflective material applied to the upper surface of the light-emitting element.

In addition to the above, there is light incident from a place where the light shielding frame (92 in FIG. 10) is to be mounted.
Further, since the light is emitted from the lateral direction with respect to the light receiving element 13, the reaction of the light receiving element 13 due to this light is weak. Therefore, the light shielding frame 92 can be omitted.

FIG. 12 shows the printed wiring board 72 shown in FIG.
Shows the state after molding of the transparent material 97 when the light-shielding frame 92 is omitted, and the transparent material 97 forms the package 61 by cutting the printed wiring board 72. Although the method of manufacturing the photocoupler shown in FIG. 6 has been described, the photocouplers of other embodiments can be manufactured in the same manner.

The embodiments of the present invention have been described above. The term “transparent material” or “reflective member” in the above text refers to the transparency or reflection of light emitted from a light emitting element used in a photocoupler. May be visibly opaque and non-reflective if is near infrared light.

[0037]

As described above, according to the present invention, since an expensive lead frame is not provided, it is easy to reduce the cost, the manufacturing process is simplified, mass production is easy, and the structure is simple. Therefore, it is easy to reduce the size, which is advantageous for assembling the electronic circuit device. Further, there is no unstable element in the structure, and the quality at the time of mass production becomes stable.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a photocoupler according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional side view of the photocoupler.

FIG. 3 is a partially cutaway perspective view of a photocoupler according to a second embodiment of the present invention.

FIG. 4 is a partially cutaway perspective view of a photocoupler according to a third embodiment of the present invention.

FIG. 5 is a vertical sectional side view of a photocoupler according to a third embodiment.

FIG. 6 is a partially cutaway perspective view of a photocoupler according to a fourth embodiment of the present invention.

FIG. 7 is a plan view of a printed wiring board.

FIG. 8 is a partially enlarged plan view of a printed wiring board.

FIG. 9 is a partially enlarged view showing terminals formed on the back surface side of the printed wiring board.

FIG. 10 is a simplified plan view of a printed wiring board provided with a light shielding frame.

FIG. 11 is an enlarged partial cross-sectional view taken along the line AA in FIG.

FIG. 12 is a plan view of a printed circuit board showing a state in which a transparent material for forming a package is formed.

FIG. 13 is a partially cutaway perspective view of a photocoupler shown as a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Printed wiring board 12 Light emitting element 13 Light receiving element 15, 18, 45, 48 Conductive wire 20, 31, 51, 61 Package 21, 32, 52 Light shielding cover 22, 33, 53 Air gap 62 Reflector 72 Before cutting Printed circuit board 73 Copper foil section before cutting 74, 75, 76, 77 Electrode before cutting 92 Light shielding frame before cutting 94 Transparent material before cutting 95 Reflecting material before cutting 96 Reflecting surface 97 Transparent material before cutting

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[Procedure amendment]

[Submission date] June 10, 1999 (1999.6.1
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007]

SUMMARY OF THE INVENTION The present invention provides a photocoupler.
-Intended to solve the above problems
As a first invention, a copper foil portion having a predetermined shape is provided as an electrode.
Light-emitting element and light-receiving element at predetermined positions on the copper foil
Element, and the light emitting element and the light receiving element are
Placed inside the package and outside the package
The outer shape of the cross section including the light emitting element and the light receiving element
It is almost parallel to the line connecting the optical
The distance D between the midpoint of the optical element and the outline is
The distance between the element and the package is L,relativerefraction
When the rate is N, D ≦ (L / 2) (N²-1)^1/2  And the package has a light
Characterized by having a light-shielding cover with a logical interval.
A photocoupler is proposed.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

FIG. 2 is a vertical side view of the photocoupler. In this figure, the light of the light emitting element 12 is transmitted to a package 20 located immediately above the intermediate point between the light emitting element 12 and the light receiving element 13.
At the point A, and enters the light receiving element 13. Light emitting element 12
The condition for total reflection of light at point A is that the relative refractive index between the transparent material used for the package 20 and its out-of-plane is N,
Is represented by the following equation, where θ is the incident angle of light at However,
The out-of-plane is air outside the plane of the package 20. N · Sin θ ≧ 1 (1)

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

The above condition is when the point A of the package 20 is in contact with air. Therefore, a gap 22 is provided between the light-shielding cover 21 and the package 20. Also,
The point A of the package 20 is other than air (package 2
0), the refractive index of the contacting material is m, the refractive index of the transparent material of the package 20 is p, and the relative refractive index N = p / m. The condition of the above D can be obtained. However, p> m. Under such conditions, the inside of the space 22 may be formed.

Claims (4)

[Claims] An arrangement having a copper foil portion of a predetermined shape as an electrode.
A light emitting element and a light receiving element at predetermined positions of the copper foil portion of the wire substrate;
The light emitting element and the light receiving element are packaged in a transparent material.
Inside the package and the external shape of the package
The outline of the cross section including the light emitting element and the light receiving element is
The light emitting element and the light receiving element are almost parallel to the line connecting the
The distance D between the middle point of the and the outline is the light emitting element and the light receiving element.
Is the distance L, and the total refractive index between the package and its out-of-plane is N.
D ≦ (L / 2) (N²-1)^1/2  And the package has a light
Characterized by having a light-shielding cover with a logical interval.
Photocoupler. 2. A light emitting element and a light receiving element are provided at predetermined positions of the copper foil part of a wiring board provided with copper foil parts of a predetermined shape as electrodes, and the wiring board between the light emitting element and the light receiving element is provided on the wiring board. The photocoupler according to claim 1, wherein a hole is provided. 3. A light emitting element and a light receiving element are provided at predetermined positions of the copper foil part of a wiring board having a copper foil part of a predetermined shape as an electrode, and the light emitting element and the light receiving element are packaged in a transparent material.
2. The photocoupler according to claim 1, wherein said photocoupler is disposed inside said package and a reflection material is provided on an outer surface of said package. 4. A wiring board in which a first electrode on which a light receiving element is mounted and a second electrode on which a light emitting element is mounted are arranged in a matrix, respectively, and the light receiving elements are provided on the first and second electrodes. And a light emitting element, respectively, and the light receiving element, the lead wire connection terminal of the light emitting element and a predetermined electrode formed on the wiring board are connected by a lead wire, and then the package is mounted on the wiring board. The light receiving element and the light emitting element are disposed inside a package made of a transparent material, and a reflection material is provided on the outer surface of the package. Photocoupler with light receiving element and light emitting element as one set
And manufacturing a plurality of photocouplers.