JPH01220482A - Optoisolator - Google Patents

Abstract

PURPOSE:To improve a current transfer ratio from a light emitting element to a photodetector, by reflecting light emitted from the light emitting element with a concave reflecting surface that is provided so as to face the light emitting surface of the light emitting element, and projecting the light to the photodetector. CONSTITUTION:Electric power is supplied to a light emitting element 1 which is arranged at one focal point of a reflecting surface 7a formed in an elliptic shape from a circuit pattern formed on an insulated substrate 5. The light emitting element 1 emits light. The light emitted from the light emitting element 1 is reflected from the reflecting surface 7a and condensed into a photodetector 2 that is arranged at another focal point of the reflecting surface 7a. The light projected on the photodetector 2 is transduced into electric energy and taken out to the outside through a circuit pattern 4. In this constitution, the light emitted from the light emitting element 1 is transmitted to the photodetector with almost no loss. The current transfer ratio from the light emitting element 1 to the photodetector 2 is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application: The present invention relates to an improvement in an opto-isolator that optically couples a light emitting element and a light receiving element.

[Conventional technology]

Conventionally, opto-isolators having various structures have been devised in order to improve the current transfer ratio in the opto-isolator. FIG. 7 is a diagram showing a schematic cross section of a conventional cylindrical opto-isolator and an optical path of light emitted by a light emitting element. In FIG. 7, l is a light emitting element, 2 is a light receiving element, 13
a, 13b.

14a and 14b are lead members, 15 is a wire, 16 is an insulating substrate, 17 is a light-transmitting resin, 17a is the upper end surface of the light-transmitting resin 17, and 18 is a resin case. 0 Light emitting element l is one lead member 13a The lead member 13b is electrically connected to the other lead member 13b by a wire 15. In addition, the light emitting element l and the lead member 13a-13
b and the wire 15 are integrally molded with a light-transmitting resin 17, and the upper end surface 17a of the light-transmitting resin 17 is formed into a convex lens shape. The light receiving element 2 is arranged facing the upper end surface 17a of the light-transmitting resin 17, and the lead member 1
4a and 14b. The light emitting element 1, the light receiving element 2, etc. are housed in a resin case 18.

In the cylindrical opto-isolator constructed as described above, the light emitted by the light emitting element 1 follows an optical path as shown by the arrow in FIG. That is, among the light emitted by the light emitting element 1, the light emitted directly to the upper end surface 17a of the light-transmitting resin 17 follows an optical path parallel to the central axis due to the lens effect of the upper end surface 17a formed in the shape of a convex lens. , is radiated to the light receiving element 2. Therefore, these lights contribute to improving the light transmission efficiency from the light emitting element 1 to the light receiving element 2.

[Problem to be solved by the invention]

However, among the light emitted by the light emitting element 1, the light emitted in the side direction is not directly emitted to the upper end surface 17a and does not reach the light receiving element 2, so that it is at the tip of the arrow m. Furthermore, even if the light is directly emitted to the upper end surface 17a, most of the light having a large incident angle to the upper surface 17a formed in a convex lens shape is reflected by the upper surface 17a due to Fresnel reflection. Therefore, the amount of light emitted to the light receiving element 2 is small. As described above, in the conventional cylindrical opto-isolator, there is a large amount of wasted light that does not reach the light receiving element 2, so there is a drawback that the transmission efficiency to the light receiving element 2 is poor.

In addition, in the conventional cylindrical opto-isolator, in order to efficiently radiate the light emitted from the light emitting element 1 in the side direction to the upper end surface 17a, the lead members 13a-13b on which the light emitting element 1 is mounted have a parabolic shape. Some reflectors are installed.

However, with respect to this reflecting mirror, the light emitting element 1 cannot be regarded as a point light source even approximately, and the reflected light cannot be sufficiently controlled by the reflecting mirror. Even if the light emitted in the side direction is reflected by the reflecting mirror, only the negative part of the light can reach the light receiving element 2, which has the same drawback as described above.

Furthermore, some opto-isolators using reflectors include
There is an opto-isolator called the DIP type. Section 8: This is a diagram showing the new surface of a conventional DIP type optoisolator and the optical path of the light emitted by the light emitting element. In Fig. 8, 1 is the light emitting element, 2 is the light receiving element, and 13 and 14 are the leads. Member, 17 is a light-transmitting resin, 19 is a white resin, 19
a is white+reflecting surface of JI resin 19 0 The light emitting element 1 is mounted on the lead member 13, while the light receiving element 2 is mounted on the lead member 14, and are electrically connected to each other by wires not shown. The light-emitting element 1 and the light-receiving element 2 are mounted facing each other in the hollow part of the white resin 19,
The hollow portion 19 is filled with a light-transmitting resin 17.

The light-emitting element 1 and the light-receiving element 2 are designed to be close to each other as far as the dielectric strength allows, and to make the current transfer ratio as large as possible.

In the DIP type opto-isolator configured as described above, among the light emitted by the light emitting element 1, the light emitted forward directly reaches the light receiving element 2, as shown by the arrow in FIG. However, most of the light does not directly reach the light receiving element 2 and is emitted onto the reflective surface 19a of the white resin 19. Some of the light reflected by the reflective surface 19a reaches the light receiving element 2, but this is only a portion. Therefore, out of the light emitted by the light emitting element 1, the light reflected by the reflecting surface 19a is not effectively radiated to the light receiving element 2, which has the disadvantage of poor transmission efficiency, similar to the cylindrical type.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide an opto-isolator that can improve the current transfer ratio from a light emitting element to a light receiving element.

(Means for Solving Problem L'!) An opto-isolator according to the present invention for achieving the above object includes a light-emitting element, a light-emitting lead portion for supplying power to the light-emitting element, and a light-emitting lead portion for supplying power to the light-emitting element. A light-receiving element that receives emitted light and converts it into electricity, a light-receiving lead portion that extracts power from the light-receiving element, and a concave reflector provided opposite to the light-emitting surface of the light-emitting element and the light-receiving surface of the light-receiving element. 114 so that the light emitted by the light emitting element is reflected by the concave reflecting surface and then radiated to the light receiving element.

Further, another opto-isolator according to the present invention for achieving the above object includes a light emitting element, a light emitting lead part for supplying power to the light emitting element, and a light emitting element that receives light emitted from the light emitting element. A light receiving element for iCL conversion, a light receiving lead portion for extracting power from the light receiving element, a first concave reflecting surface provided opposite to the light emitting surface of the light emitting element, and a first concave reflecting surface facing the light receiving surface of the light receiving element. and a second concave reflective surface provided opposite to the first concave reflective surface, and the light emitted by the light emitting element is reflected by the m l concave reflective surface, Furthermore, after being reflected by the second concave reflecting surface, the light is radiated to the light receiving element.

[Effect]

The opto-isolator according to the present invention has the above configuration,
To efficiently radiate the light emitted by the light-emitting element to the light-receiving element by supplying power to the light-emitting element from the light-emitting lead part, reflecting the light emitted by the light-emitting element on a concave reflecting surface, and then radiating it to the light-receiving element. Can be done. Further, the electrical energy photoelectrically converted by the light receiving element is taken out to the outside through the light receiving lead section.

Further, another opto-isolator according to the present invention has the above-described configuration, supplies power to the light emitting element from the light emitting lead part, reflects light emitted by the light emitting element on the first concave reflecting surface,
Furthermore, the light emitted by the light emitting element can be efficiently radiated to the light receiving element by reflecting the light on the second concave reflecting surface disposed opposite to the first concave reflecting surface and then emitting the light to the light receiving element. can. Further, the electrical energy photoelectrically converted by the light receiving element is taken out to the outside through the light receiving lead section.

〔Example〕

A first embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a diagram showing a schematic cross section of an optoisolator according to a first embodiment of the present invention and an optical path of light emitted by a light emitting element. In FIG. 1, 1 is a light emitting element, 2 is a light receiving element, 3 is a circuit pattern for the light emitting element 1, 4 is a circuit pattern for the light receiving element 2, 5 is an insulating substrate, and 6 is a light transmitting material t! 1
．． 7 is the L1 resin case, and 7a is the reflective surface of the resin case 7.

The light emitting element 1 is mounted on a circuit pattern 3 formed on the upper surface of an insulating substrate 5, and the light receiving element 2 (for example, a photodiode) is mounted on a circuit pattern 4. Circuit pattern (
(not shown). Resin case 7
is arranged so as to cover the light emitting element 1 and the light receiving element 2, and its reflecting surface 7a is formed in the shape of an ellipsoid. for example,
The resin case 7 is made by forming an ellipsoidal concave part on a flat resin, and mirror-finishing the concave part by plating, metal vapor deposition, etc. to form a reflective surface 7a. A light emitting element 1 is arranged at one of the two focal points of the reflecting surface 7a, facing the reflecting surface 7a, and a light receiving element 2 is arranged at the other focal point. A hollow portion within the resin case 7 is filled with a light-transmitting material 6.

Note that the light-transmitting material 6 may be glass, for example, low-melting-point glass, and the light-transmitting material 6 filling the space between the light-emitting element 1, the light-receiving element 2, and the resin case 7 protects each element and protects the light-emitting element. The purpose of this is to improve the efficiency of light extraction from 1. The bendable light-transmitting material 6 may be formed by partially molding only around the light-emitting element 1 and the light-receiving element 2, without filling the entire hollow part in the resin case 7. Also, it is easy to manufacture. When importance is placed on transparency, the surfaces of the circuit pattern 3 formed on the insulating substrate 5 and the light emitting element 1 mounted thereon are coated with a light-transmitting material 6, for example, by spray coating. Failures due to shocks, vibrations, etc. may be prevented. On the other hand, if there is no need to take into account disconnection or failure of the light-emitting element 1 and light-receiving element 2 due to shocks, vibrations, etc., it may remain hollow.
Gas or the like may be filled in the hollow portion as necessary. The same applies to other embodiments described below.

According to the above configuration, power is supplied to the light emitting element 1 which is focused on one focal point of the reflecting surface 7a formed in an elliptical shape by the circuit pattern 3 formed on the insulating substrate 5, and the light emitting element 1 emits light. do. The light emitted by the light emitting element 1 is reflected by the reflecting surface 7a, as shown by the arrow in FIG. 1, and then focused on the light receiving element 2 arranged at the other focal point of the reflecting surface 7a. In this way, the reflective surface 7a of this embodiment is formed in an elliptical shape, and the light emitting element 1 and the light receiving element 2 are respectively arranged at the two focal points of the reflective surface 7a, so that the light emitted by the light emitting element l is can be effectively transmitted to the light receiving element 2 without any loss. Further, the light emitted to the light receiving element 2 is converted into electrical energy, and the electrical energy is taken out to the outside via the circuit pattern 4.

According to the embodiment described above, the light emitted by the light emitting element 1 can be efficiently focused on the light receiving element 2 by the reflective surface 7a, so that there is no loss of light and the transmission efficiency can be improved. This contributes to improving the current transfer ratio of the opto-isolator. Note that the current transfer ratio
If C, then X = (I c / I r ) X 1
00 (%) and can be expressed as −ζ.

Further, according to the above embodiment, the structure is simple, so
Opto-isolators can be manufactured easily and their heritage can be improved. Furthermore, since the light-emitting element 1 and the light-receiving element 2 can be arranged on the same plane, it is thinner than a conventional opto-isolator in which the light-emitting element 1 and the light-receiving element 2 are arranged facing each other. can be manufactured.

In this embodiment, a case has been described in which the reflecting surface 7a uses a part of the ellipsoidal surface, but the reflecting surface 7a may use the entire ellipsoidal surface or another part.

FIG. 2 is a diagram showing a modification of the first embodiment.

In FIG. 2, 6a is the upper end surface of the light-transmitting material 6. In FIG.

In addition, in the modified example of the first embodiment shown in FIG. 2 and in the second to fourth embodiments described below, those having the same m functions as the first embodiment shown in FIG. 1 above are the same. The 0-piece variant, whose detailed explanation is omitted by attaching the symbol, is
This is a simplified version by omitting the resin 7 in the first practical example. That is, the upper end surface 6a of the light-transmitting material tel 6 is formed into an ellipsoidal shape, and the surface of this upper end surface 6a is treated with plating or metal vapor deposition to form a reflective surface. As a result, the same functions and effects as in the first embodiment can be produced. This means that
The same applies to the second to fourth embodiments described below.

FIG. 3 is a diagram showing a schematic cross section of a second embodiment of the present invention and an optical path of light emitted by a light emitting element. 33 in Figure 3
1 is a circuit pattern for the light emitting element 1, 10a and IOb are lead members for the light receiving element 2, 5a is an insulating substrate, 7b is a reflective surface of the resin case 7, and 8 is a light-transmitting insulating substrate. still,
The light receiving element 2 is a planar element (for example, a photoconductive cell). The light emitting element 1 is mounted on a circuit pattern 3a formed on the lower surface of a light-transmissive insulating substrate 8, and is electrically connected to another rgJ path pattern (not shown) by a wire (not shown). On the other hand, the light receiving element 2 is attached to the insulating substrate 5a disposed at the -F section of the light-transmissive insulating substrate 8, and connected to the lead members 10a-10b. Also,
The light emitting element 1, the light receiving element 2, etc. are housed in a resin case 7, and a parabolic reflecting surface 7b with the light emitting element 1 as a focal point is formed at the lower part of the inner surface of the resin case 7. A hollow portion within the resin case 7 is filled with a light-transmitting material 6.

According to the above configuration, the light emitted by the light emitting element 1 is reflected by the reflecting surface 7b in a direction parallel to the central axis of the reflecting surface 7b as shown by the arrow in FIG. is radiated to. Therefore, the light emitted by the light emitting element 1 can be effectively transmitted to the light receiving element 2 without significant loss. Other functions and effects are similar to those of the first embodiment.

Note that the circuit pattern 3a formed on the light-transmissive insulating substrate 8
The line width is 20IIm or less, and the diameter of the reflective surface 7b is 5
Even in the case of mm, the loss due to the shadow between the light emitting element 1 and the circuit pattern 3a is less than 1%, so the influence of the shadow does not pose a particular problem.

FIG. 4 shows 1 of the third embodiment of the present invention. ! [FIG. 3] A diagram showing a schematic cross section and an optical path of light emitted by a light emitting element. Further, FIG. 5 shows the arrangement of the light emitting element and the light receiving element. Fourth
In the figure and FIG. 5, 3b and 3c are circuit patterns for the light emitting element 1, lOa and 10b are lead members for the light receiving element 2, 5a is an insulating substrate, 7b is a reflective surface of the resin case 7, and 9
is a wire.

In this embodiment, the light-transmitting insulating substrate 8 in the second embodiment is omitted, and the light-emitting element 1, the light-receiving element 2, and the circuit patterns 3b and 3c are integrally arranged on the lower surface of the insulating substrate 5a. be. That is, as shown in FIG.
A groove 2a is provided in the center of the light emitting element l.
And circuit patterns 3b and 3c are arranged. The light emitting element 1 is attached to one circuit pattern 3b and electrically connected to the other circuit pattern 3c by a wire 9. The other configurations are the same as those of the second embodiment. Note that power is supplied to the circuit patterns 3b and 3c shown in FIG. 5 from their back surfaces.

With the above configuration, it is possible to produce the same functions and effects as those of the second embodiment.

FIG. 6 is a diagram showing a schematic cross section of a fourth embodiment of the present invention and an optical path of light emitted by a light emitting element. 3d in Figure 6
4d is the circuit pattern for the light-emitting element 1, 7C is the lower reflective surface of the resin case 7, 7d
is the upper reflective surface of the resin case 7, 8 is a light-transmitting insulating substrate, the light-emitting element 1 is mounted on a circuit pattern 3d formed on the lower surface of the light-transmitting insulating substrate 8, and the light-receiving element 2 is: They are mounted on circuit patterns 4d formed on the upper surface of the light-transmissive insulating substrate 8, and are electrically connected to other circuit patterns (not shown) by wires (not shown). The light-emitting element 1 and the light-receiving element 2 are housed in a resin case 7. The lower reflective surface 7C of the resin case 7 has a parabolic shape with the light-emitting element 1 as the focal point, and the upper reflective surface 7d has the light-receiving element 2 as the focal point. Each is formed into a parabolic shape. A hollow portion within the resin case 7 is filled with a light-transmitting material 6. Note that the light-transmitting material 6 may be filled only in the hollow portion between the light emitting element 1 and the lower reflective surface 7C.

According to the above configuration, power is supplied to the light emitting element 1 by the circuit pattern 3d formed on the lower surface of the light-transmissive insulating group +M8, and the light emitting element 1 emits light. And light emitting element 1
The light emitted from the lower reflective surface 7C as shown by the arrow in Figure 6
The light is reflected in a direction parallel to the central axis of the reflecting surface 7C. Further, the parallel light is reflected by the upper reflecting surface 7d disposed opposite to the light receiving element 2, becomes convergent light, and then condensed onto the light receiving element 2 disposed at the focal point of the upper reflecting surface 7d. Therefore, even if the light-emitting surface of the light-emitting element 1 and the light-receiving surface of the light-receiving element 2 are arranged in opposite directions, the light emitted by the light-emitting element 1 can be effectively transmitted to the light-receiving element 2 without any loss. Also, 1? of the circuit patterns 3d and 4d formed on the light-transmissive insulating substrate 8? ! The width is 20 μm or less, and even if the diameter of the reflective surfaces 7C and 7d in FIG.
Since the loss of ti due to the shadow of d is less than a few percent, the amount of the shadow is not a particular problem. Other functions and effects are the same as those of the first embodiment.

In the first to fourth implementations υ:j above, the case where the light-emitting lead part is an insulating substrate on which a circuit pattern is formed or a light-transmitting insulating substrate is explained, but the light-emitting lead part is a thin lead. The same applies to the light-receiving lead portion, which may use a frame.

Furthermore, in the first to fourth embodiments described above, the case where the concave reflecting surface is formed in a parabolic or ellipsoidal shape has been described, but the concave reflecting surface is formed by combining a plurality of small planes. Alternatively, it may be formed into a parabolic or ellipsoidal shape.

〔Effect of the invention〕

As explained above, according to the present invention, the light emitted by the light emitting element is reflected by the concave reflecting surface provided opposite the light emitting surface of the light emitting element and then radiated to the light receiving element. It is possible to provide an opto-isolator that can efficiently radiate light to a light-receiving element and improve the current transfer ratio from the light-emitting element to the light-receiving element.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic cross section of an opto-isolator according to a first embodiment of the present invention and an optical path of light emitted by a light emitting element,
FIG. 2 is a diagram showing a modification of the first embodiment, FIG. 3 is a diagram showing a schematic cross section of the second embodiment of the invention and the optical path of light emitted by the light emitting element, and FIG. FIG. 5 is a diagram showing a schematic cross section of the third embodiment and the optical path of light emitted by the light emitting element, FIG. 5 is a diagram showing the arrangement of the light emitting element and the light receiving element, and FIG. 6 is a schematic diagram of the fourth embodiment of the present invention. FIGS. 7 and 8 are diagrams showing a cross section and an optical path of light emitted by a light emitting element. FIGS. 7 and 8 are diagrams showing a schematic cross section of a conventional opto-isolator and an optical path of light emitted by a light emitting element. DESCRIPTION OF SYMBOLS 1... Light emitting element, 2... Light receiving element, 3, 4... Circuit pattern, lO... Lead member, 5, 5a... Insulating substrate, 6... Light transmitting material, 6a.・Top end surface, 7
... Resin case, 7a, 7b, 7C, 7d... Reflective surface, 8... Light-transmissive insulating substrate, 9... Wire. Applicant Iwasaki Electric Co., Ltd. Figure 5 Figure 6

Claims (15)

[Claims] (1) A light-emitting element, a light-emitting lead part that supplies power to the light-emitting element, a light-receiving element that receives light emitted by the light-emitting element and converts it into electricity, and a light-receiving lead part that extracts power from the light-receiving element. , comprising a concave reflective surface provided opposite to the light emitting surface of the light emitting element and the light receiving surface of the light receiving element,
An opto-isolator characterized in that the light emitted by the light emitting element is reflected by the concave reflecting surface and then radiated to the light receiving element. (2) The opto-isolator according to claim 1, wherein the concave reflective surface is ellipsoidal. (3) The opto-isolator according to claim 2, wherein the light emitting element and the light receiving element are respectively arranged at two different focal points of the concave reflective surface. (4) The opto-isolator according to claim 1, wherein the concave reflective surface is parabolic. (5) The opto-isolator according to claim 4, wherein the light emitting element is arranged at the focal point of the concave reflective surface, and the light receiving element is a planar element and is arranged behind the light emitting element. (6) The opto-isolator according to claim 4, wherein the light emitting element is arranged at the focal point of the concave reflecting surface, and the light receiving element is a planar element and arranged around the light emitting element. (7) A light-emitting element, a light-emitting lead part that supplies power to the light-emitting element, a light-receiving element that receives light emitted by the light-emitting element and converts it into electricity, and a light-receiving lead part that extracts power from the light-receiving element. , a first concave reflective surface provided opposite to the light emitting surface of the light emitting element, and a second concave reflective surface provided opposite to the light receiving surface of the light receiving element and opposite to the first concave reflective surface. a concave reflective surface, the light emitted by the light emitting element is reflected by the first concave reflective surface;
An opto-isolator characterized in that the opto-isolator is configured to emit light to the light receiving element after being reflected by the concave reflecting surface of the light receiving element. (8) The concave reflective surface is a parabolic reflective surface, the light emitting element is disposed at the focal point of the first concave reflective surface, and the light receiving element is located at the focal point of the second concave reflective surface. 8. The optoisolator according to claim 7, wherein the optoisolator is located at a focal point. (9) A space between the light-emitting element, the light-receiving element, and the concave reflective surface is filled with a light-transmitting material.
7. The opto-isolator according to any one of 6 to 6. (10) A space between the light emitting element and the first concave reflective surface and a space between the light receiving element and the second concave reflective surface are filled with a light-transmitting material. Optoisolators described in . (11) The opto-isolator according to any one of claims 1 to 10, wherein the concave reflective surface is formed by vapor-depositing metal on a concave portion provided on a flat resin. (12) The concave reflective surface is formed by forming a convex surface of the light-transmitting material facing the light-emitting element and the light-receiving element, and depositing metal on the convex surface. 10. The opto-isolator of claim 9. (13) The first concave reflective surface is formed by forming a convex surface of the light-transmitting material facing the light emitting element, and depositing metal on the convex surface. The second concave reflective surface is formed by forming a convex surface of the light-transmitting material facing the light-receiving element, and depositing metal on the convex surface. The optoisolator according to claim 10. (14) Any one of claims 1 to 13, wherein the lead portion includes an insulating substrate on which a circuit pattern is formed, and the light emitting element and the light receiving element are mounted on the circuit pattern of the insulating substrate and wire bonded. Optoisolator described in the above. (15) Claims 1 to 1, wherein the lead portion includes a lead frame, and the light emitting element and the light receiving element are attached to the lead frame and wire bonded.
3. The opto-isolator according to any one of 3.