WO2018105358A1 - Photocoupler - Google Patents

Abstract

A photocoupler (1) has one or a plurality of mirrors arranged on a surface of an optically transmissive resin member (60) encapsulating a light emitting element (31) and a light reception element (32). The one or a plurality of mirrors are arranged such that each of the one or plurality of mirrors specularly reflects incident light to guide laser light emitted from the light emitting element (31) to a light reception surface of the light reception element (32). Preferably, the surface of the resin member may include one or a plurality of reflecting surfaces (13, 15) that function as the one or plurality of mirrors. In this case, the incident angle of laser light to each of the reflecting surfaces (13, 15) is greater than a critical angle which is the angle at which the incident light is total internally reflected.

Description

Photo coupler

This disclosure relates to photocouplers.

For example, in the photocoupler having a general configuration disclosed in FIG. 5 of Japanese Patent Application Laid-Open No. 08-008457 (Patent Document 1), the light emitting element mounted on the primary side lead frame and the secondary side lead frame are mounted. The light receiving elements thus arranged are arranged to face each other. A light emitting diode (LED: Light Emitting Diode) is used as the light emitting element, and a photodiode is used as the light receiving element. Each element and the lead frame are connected by a bonding wire. The light emitting element and the light receiving element are sealed with a light transmissive resin.

Japanese Patent Laying-Open No. 2015-026704 (Patent Document 2) discloses a photocoupler having a configuration different from the above. Specifically, the photocoupler disclosed in this document includes a light emitting element and a light receiving element provided on a substrate, a translucent first resin that seals the light emitting element and the light receiving element, and a translucent covering the periphery of the first resin. Second resin and a reflective third resin covering the top surface of the first resin. The third resin is a white resin containing a reflective filler such as titanium oxide. The third resin diffuses and reflects the light emitted from the light emitting element and passed through the first resin, and returns to the first resin again.

Japanese Patent Laid-Open No. 08-008457 Japanese Patent Laying-Open No. 2015-026704

The above-described conventional photocoupler has problems that the power loss is large and the transmission speed cannot be increased.

Specifically, the problems in the case of the photocoupler having the general configuration disclosed in FIG. 5 of the above-mentioned Patent Document 1 are as follows. First, when a light-emitting diode is used as the light-emitting element, the transmission rate is 100 Mbps (megabits per second) at most, and the transmission rate cannot be increased any more. Even if the light emitting element is changed to a semiconductor laser element such as a vertical cavity surface emitting laser (VCSEL) element in order to perform high-speed communication on the order of Gbps (Gigabit per second), a lead frame is used. Therefore, the power loss due to impedance mismatching becomes large. Therefore, high-speed signal transmission cannot be performed after all.

The problems in the case of the photocoupler having the configuration described in Patent Document 2 are as follows. When an LED is used as the light emitting element, the LED emits isotropic light, that is, it emits light having a power equal to all angles, so that it is reflected by the reflective third resin and is reflected on the light receiving element. The reaching light is limited to a part emitted from the LED. For this reason, the power loss of light is large.

In addition, when a semiconductor laser element such as a VCSEL element is used as a light emitting element in order to perform high-speed signal transmission on the order of Gbps (gigabit per second), the semiconductor laser beam has a strong directivity, that is, the spread of the laser beam. The small angle causes a problem, and the ratio of the light that is reflected by the third resin and reaches the light receiving element is reduced. For this reason, the photocoupler having the configuration of Patent Document 2 cannot use a semiconductor laser element, and therefore cannot perform high-speed communication in the Gbps order.

This disclosure takes the above-mentioned problems into consideration, and an object thereof is to provide a photocoupler capable of reducing the power loss of light and improving the signal transmission speed.

A photocoupler according to an aspect of the present disclosure covers a substrate, a light emitting element that is disposed on the main surface of the substrate and emits laser light, a light receiving element that is disposed on the main surface of the substrate, and a main surface of the substrate. Thus, a translucent resin member that seals the light emitting element and the light receiving element, and one or a plurality of mirrors disposed on the surface of the resin member are provided. The one or more mirrors are arranged so that the laser light emitted from the light emitting element is guided to the light receiving surface of the light receiving element by each of the one mirror or the plurality of mirrors regularly reflecting incident light. ing.

According to the above configuration, the laser light is used for signal transmission, and the laser light is guided from the light emitting element to the light receiving element by the regular reflection at the mirror, so that the power loss of the light can be reduced. Furthermore, since a high-frequency compatible substrate can be used by arranging a light emitting element and a light receiving element on the substrate, it is suitable for high-speed signal transmission on the order of Gbps.

In one embodiment, the surface of the resin member may include one or more reflecting surfaces that function as one or more mirrors. In this case, the incident angle of the laser light on each reflecting surface is larger than the critical angle that is the angle at which the incident light is totally reflected. Thus, by configuring the mirror as a reflecting surface on the surface of the resin member, it is possible to manufacture a photocoupler with a simple configuration at low cost.

The one or more reflecting surfaces described above may be configured to include a first reflecting surface and a second reflecting surface. In this case, the first reflecting surface forms an angle of 45 degrees with the main surface of the substrate, and the second reflecting surface forms an angle of 90 degrees with the first reflecting surface. The light emitting element emits laser light toward the first reflecting surface. The laser beam specularly reflected by the first reflecting surface reaches the second reflecting surface, and the laser beam specularly reflected by the second reflecting surface reaches the light receiving surface of the light receiving element.

According to the above configuration, the incident angle of the laser beam to each of the first reflecting surface and the second reflecting surface is 45 degrees, which is a value larger than the critical angle of the resin material. Therefore, the first reflection surface and the second reflection surface can totally reflect incident light. In this specification, when an angle of 45 degrees or 90 degrees is defined, it does not mean that the angle must be exactly 45 degrees or 90 degrees, and manufacturing errors are included within a range in which the optical path is not significantly shifted. Say the range.

In the above embodiment, the resin member may have a first groove and a second groove that are recessed from the surface opposite to the substrate toward the substrate. In this case, the surface that defines the first groove includes the first reflective surface, and the surface that defines the second groove includes the second reflective surface.

In other embodiments, the one or more mirrors may include a reflector disposed on the surface of the resin member. The laser light is regularly reflected at the interface between the resin member and the reflecting plate. According to this configuration, the laser beam can be totally reflected by the reflecting plate regardless of the incident angle of the laser beam to the reflecting plate.

In the one embodiment and the other embodiments described above, the resin member has a first internal space, and the surface defining the first internal space is a first lens surface protruding into the first internal space. May be included. In this case, the laser light emitted from the light emitting element reaches one of the one mirror or the plurality of mirrors after passing through the first lens surface.

According to the above configuration, the laser light emitted from the light emitting element can be collimated to make the light substantially parallel, so that the power loss of light can be further reduced.

In the above-described embodiment and other embodiments, the surface defining the first internal space may include a second lens surface protruding into the first internal space. In this case, the laser light regularly reflected by one of the one mirror or the plurality of mirrors reaches the light receiving surface of the light receiving element after passing through the second lens surface.

According to the above configuration, since the laser light can be condensed on the light receiving surface of the light receiving element, the light receiving surface of the light receiving element can be used even if there is a deviation in the arrangement of the light receiving elements when the light receiving element is mounted on the substrate. Laser light can be guided upward.

In the above-described embodiment and other embodiments, the substrate may be located on the opposite side to the first internal space with the first lens surface and the second lens surface interposed therebetween. Alternatively, the substrate may be located on the opposite side of the first lens surface and the second lens surface with the first internal space interposed therebetween.

As a modification, the resin member further includes a second internal space different from the first internal space, and a surface defining the second internal space is a second lens surface protruding into the second internal space. May be included. In this case, the laser light regularly reflected by one of the one mirror or the plurality of mirrors reaches the light receiving surface of the light receiving element after passing through the second lens surface.

In still another embodiment, the resin member has an internal space, and the surface defining the internal space may include a bottom surface and an upper surface that face each other with the internal space interposed therebetween. In this case, the substrate is located on the opposite side of the internal space with the bottom surface in between. Furthermore, the one or more mirrors may include a reflector disposed on the top surface. In this case, the bottom surface includes a first lens surface that guides the laser light emitted from the light emitting element to the reflecting plate, and a second lens surface that guides the laser light regularly reflected by the reflecting plate to the light receiving surface of the light receiving element. Including. According to this configuration, the laser beam can be totally reflected by the reflecting plate regardless of the incident angle of the laser beam to the reflecting plate.

In each of the above embodiments, the light emitting element may include a vertical cavity surface emitting laser element.

In each of the above embodiments, the photocoupler may further include a first integrated circuit chip that is disposed on the main surface of the substrate and supplies a drive signal to the light emitting element.

In each of the above embodiments, the photocoupler may further include a second integrated circuit chip that is disposed on the main surface of the substrate and that processes an output signal of the light receiving element.

In each of the above embodiments, the photocoupler is disposed on the back surface of the substrate opposite to the main surface of the substrate, the first ground terminal for the light emitting element, and disposed on the back surface of the substrate. And a second ground terminal for the light receiving element separated from each other.

In yet another embodiment, the substrate may be separated into a first substrate and a second substrate. In this case, the light emitting element is disposed on the main surface of the first substrate, and the light receiving element is disposed on the main surface of the second substrate. The resin member includes a first sealing portion that seals the light emitting element by covering the main surface of the first substrate, and a second seal that seals the light receiving element by covering the main surface of the second substrate. And a top plate portion that connects the surface of the first sealing portion opposite to the first substrate and the surface of the second sealing portion opposite to the second substrate. The surface of the top plate includes one or more reflecting surfaces that function as the one or more mirrors described above. The incident angle of the laser light on each reflecting surface is larger than the critical angle that is the angle at which the incident light is totally reflected.

The above configuration can be suitably used when it is necessary to increase the distance between the transmission-side terminal and the reception-side terminal of the photocoupler in order to improve the dielectric strength, such as a medical device. .

In the configuration separated into the first and second substrates as described above, the first sealing portion has the first internal space, and the surface defining the first internal space is the first internal space. A first lens surface protruding into the space may be included. In this case, the laser light emitted from the light emitting element reaches one of the one reflecting surface or the plurality of reflecting surfaces after passing through the first lens surface. Further, the second sealing portion may have a second internal space, and the surface defining the second internal space may include a second lens surface protruding into the second internal space. In this case, the laser beam specularly reflected by either the one reflecting surface or the plurality of reflecting surfaces reaches the light receiving surface of the light receiving element after passing through the second lens surface.

According to the above configuration, the laser light emitted from the light emitting element can be collimated to make the light substantially parallel, so that the power loss of light can be further reduced. Further, since the laser beam can be condensed on the light receiving surface of the light receiving element, even if a deviation occurs in the arrangement of the light receiving element when the light receiving element is mounted on the substrate, the laser beam is applied to the light receiving surface of the light receiving element. Can lead.

A photocoupler according to another aspect of the present disclosure includes a substrate, a light emitting element that is disposed on the main surface of the substrate, emits laser light in a direction perpendicular to the substrate, and a light receiving element that is positioned on the main surface of the substrate. A transparent resin member for sealing the light emitting element and the light receiving element is provided by covering the main surface of the substrate. The refractive index of the resin member is larger than √2. The surface of the resin member includes a first reflection surface and a second reflection surface that regularly reflect incident light. The first reflecting surface forms an angle of 45 degrees with the main surface of the substrate and is disposed at a position overlapping the light emitting element when viewed from a direction perpendicular to the substrate. The second reflecting surface forms an angle of 90 degrees with the first reflecting surface, faces the first reflecting surface with a part of the resin member interposed therebetween, and receives light when viewed from a direction perpendicular to the substrate. It arrange | positions in the position which overlaps with the light-receiving surface of an element.

According to the above configuration, the laser light is used for signal transmission, and the laser light is guided from the light emitting element to the light receiving element by the regular reflection at the mirror, so that the power loss of the light can be reduced. Furthermore, since a high-frequency compatible substrate can be used by arranging a light emitting element and a light receiving element on the substrate, it is suitable for a high-speed response on the order of Gbps.

In the other aspect described above, the resin member may have an internal space, and the surface defining the internal space may include a bottom surface and an upper surface facing each other with the internal space interposed therebetween. In this case, the substrate is located on the opposite side of the internal space with the bottom surface in between. The bottom surface is located between the light emitting element and the first reflecting surface, is located between the first lens surface projecting into the internal space, and the light emitting element and the second reflecting surface, and projects into the internal space. A second lens surface.

According to the above configuration, the laser light emitted from the light emitting element can be collimated to make the light substantially parallel, so that the power loss of light can be further reduced. Further, since the laser beam can be condensed on the light receiving surface of the light receiving element, even if a deviation occurs in the arrangement of the light receiving element when the light receiving element is mounted on the substrate, the laser beam is applied to the light receiving surface of the light receiving element. Can lead.

As described above, according to the photocoupler of the present disclosure, it is possible to reduce light power loss and improve signal transmission speed.

1 is an exploded perspective view showing a configuration of a photocoupler according to Embodiment 1. FIG. It is a top view of the photocoupler of FIG. FIG. 3 is a cross-sectional view taken along a cutting line III-III in FIG. FIG. 4 is a diagram illustrating an optical path of a laser beam from a light emitting element to a light receiving element in the cross-sectional view of FIG. 3. FIG. 4 is a flowchart showing an example of a method for manufacturing the photocoupler shown in FIGS. 1 to 3. FIG. 7 is a cross-sectional view of a photocoupler according to a modification of the first embodiment. FIG. FIG. 6 is a cross-sectional view illustrating a configuration of a photocoupler according to a second embodiment. 6 is a cross-sectional view illustrating a configuration of a photocoupler according to Embodiment 3. FIG. FIG. 6 is a cross-sectional view illustrating a configuration of a photocoupler according to a fourth embodiment. FIG. 6 is a cross-sectional view illustrating a configuration of a photocoupler according to a fifth embodiment. FIG. 10 is a cross-sectional view illustrating a configuration of a photocoupler according to a sixth embodiment. FIG. 10 is a cross-sectional view illustrating a configuration of a photocoupler according to a seventh embodiment.

Hereinafter, embodiments will be described in detail with reference to the drawings. The same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

<Embodiment 1>
[Overall configuration of photocoupler]
FIG. 1 is an exploded perspective view showing the configuration of the photocoupler according to the first exemplary embodiment. FIG. 2 is a plan view of the photocoupler of FIG. FIG. 3 is a cross-sectional view taken along section line III-III in FIG. In the following description, directions parallel to the substrate are defined as an X direction and a Y direction, and a direction perpendicular to the substrate is defined as a Z direction.

1 to 3, the photocoupler includes a substrate 30, a light emitting element 31 that emits laser light, a light receiving element 32, integrated circuit (IC: Integrated Circuit) chips 33 and 34, and a resin member 60. With.

The substrate 30 is desirably made of a material having a small dielectric loss tangent when used at a high frequency. For example, an LGA (Land Grid Array) substrate can be used so that a high-frequency signal can be transmitted. On the back surface of the LGA substrate, planar electrode terminals are arranged in a grid pattern to perform reflow soldering on the printed circuit board. In FIG. 3, four terminals 35 to 38 provided on the back surface 302 of the substrate 30 are representatively shown.

The light emitting element 31 is disposed on the main surface 301 of the substrate 30. The light emitting element 31 is, for example, a vertical cavity surface emitting laser (VCSEL) element, and emits laser light in a direction perpendicular to the substrate 30 (+ Z direction). The light emitting element 31 is fixed on the substrate 30 by, for example, solder, and is electrically connected to a conductive pattern (not shown) formed on the main surface 301 of the substrate 30 by a bonding wire (not shown).

The light receiving element 32 is disposed on the main surface 301 of the substrate 30. The light receiving element 32 is, for example, a semiconductor photodetector such as a photodiode or a phototransistor. The light receiving surface of the light receiving element 32 is directed above the substrate 30 (+ Z direction). The light receiving element 32 is fixed on the substrate 30 by, for example, solder, and is electrically connected to a conductive pattern (not shown) formed on the main surface 301 of the substrate 30 by a bonding wire (not shown).

The integrated circuit chip 33 incorporates a signal processing circuit such as a driver circuit for the light emitting element 31. The integrated circuit chip 34 incorporates a signal processing circuit such as a trans-impedance amplifier (TIA) that impedance-converts and amplifies the current signal output from the light-receiving element 32 and outputs it as a voltage signal.

As described above, a plurality of planar electrode terminals are provided on the back surface 302 of the substrate 30. These planar electrode terminals include a primary side terminal (a ground terminal 35, a power supply terminal 36, and other signal terminals (not shown)) used for the light emitting element 31 and the integrated circuit chip 33, a light receiving element 32, and Secondary terminals used for the integrated circuit chip 34 (a ground terminal 37, a power supply terminal 38, and other signal terminals (not shown)) are included. In order to be used as a photocoupler, the primary side terminal and the secondary side terminal must be electrically separated. For example, the primary side ground terminal 35 and the secondary side ground terminal 37 are electrically separated from each other, and the primary side power supply terminal 36 and the secondary side power supply terminal 38 are electrically separated from each other. Has been.

The resin member 60 is formed of a translucent resin material that transmits the laser light emitted from the light emitting element 31. As the resin member 60, for example, an epoxy resin is used. Epoxy resin is almost transparent to laser light in the 850 nm band and has a refractive index of about 1.55. The wavelength of the laser beam and the material of the resin member 60 are not limited to these.

1 to 3, the outer shape of the resin member 60 is a substantially rectangular parallelepiped shape, and includes the sealing portion 20 and the top plate portion 11. The sealing unit 20 is formed so as to cover the main surface 301 of the substrate 30, and seals the light emitting element 31, the light receiving element 32, and the integrated circuit chips 33 and 34.

A rectangular parallelepiped hole 21 is formed on the surface of the sealing portion 20 opposite to the substrate 30 (hereinafter referred to as “upper surface 25”). The bottom surface 22 of the hole 21 includes lens surfaces 23 and 24 protruding upward (+ Z direction). The lens surfaces 23 and 24 function as semi-convex lenses.

The top plate 11 is provided so as to cover the hole 21. The top plate 11 has grooves 12 and 14 that are recessed in a direction from the surface opposite to the substrate 30 (hereinafter referred to as “upper surface 17”) toward the substrate 30. The plane that defines the groove 12 has a flat reflecting surface 13 that regularly reflects the laser beam. Similarly, the plane that defines the groove 14 has a flat reflecting surface 15 that regularly reflects the laser beam.

Here, regular reflection refers to reflection with the same incident angle and reflection angle. Regular reflection is also called specular reflection. The reflecting surfaces 13 and 15 are desirably so smooth that they regularly reflect all of the incident laser light, but may partially include scattered light. As a whole, each of the reflecting surfaces 13 and 15 forms a reflected beam having a reflection angle equal to the incident angle of the incident beam.

The reflecting surface 13 forms an angle of 45 degrees with respect to the main surface 301 of the substrate 30. The reflection surface 15 forms an angle of 45 degrees with respect to the main surface 301 of the substrate 30 and forms an angle of 90 degrees with respect to the reflection surface 13. In the case of FIG. 3, since the upper surface 17 of the top plate portion 11 and the main surface 301 of the substrate 30 are substantially parallel, the angle θ ₁ formed by the upper surface 17 of the top plate portion 11 and the reflecting surface 13 is 45 degrees. The angle θ ₂ formed by the upper surface 17 of the top plate 11 and the reflecting surface 15 is 45 degrees. Further, the distance from the reflecting surface 13 to the main surface 301 of the substrate 30 is substantially equal to the distance from the reflecting surface 15 to the main surface 301 of the substrate 30.

When viewed from a direction perpendicular to the main surface 301 of the substrate 30, the reflecting surface 13, the lens surface 23, and the light emitting element 31 overlap each other, and the lens surface 23 is located between the reflecting surface 13 and the light emitting element 31. It is desirable that the optical axis of the lens surface 23 passes through the center of the emission surface of the light emitting element 31. Similarly, when viewed from the direction perpendicular to the main surface 301 of the substrate 30, the reflecting surface 15, the lens surface 24, and the light receiving element 32 overlap each other, and the lens surface 24 is located between the reflecting surface 15 and the light receiving element 32. ing. It is desirable that the optical axis of the lens surface 24 passes through the center of the light receiving surface of the light receiving element 32.

[Operation of photocoupler]
Next, the operation of the photocoupler 1 described with reference to FIGS. 1 to 3 will be described.

FIG. 4 is a diagram showing an optical path of a laser beam from the light emitting element to the light receiving element in the cross-sectional view of FIG. The optical path 70 of the laser beam is indicated by a broken line in FIG.

The integrated circuit chip 33 drives the light emitting element 31 based on the input signal. As a result, the light emitting element 31 emits laser light in a direction perpendicular to the substrate 30. The laser light emitted from the light emitting element 31 is not necessarily a parallel light beam but has a spread. The lens surface 23 collimates the laser light emitted from the light emitting element 31 into parallel light.

The laser light that has passed through the lens surface 23 passes through the internal space 61 defined by the hole portion 21 and then enters the top plate portion 11 from the lower surface 18 of the top plate portion 11. Thereafter, the laser beam is regularly reflected by the reflecting surface 13.

Here, the incident angle θi to the reflecting surface 13 and the reflection angle θr are equal to 45 degrees. If the refractive index of the resin member 60 is n, the incident light on the reflecting surface 13 is totally reflected if the incident angle θi is larger than the critical angle θ ₀ that satisfies sin θ ₀ = n. When the incident angle θi is 45 degrees, the incident light is totally reflected if the refractive index n is larger than √2. The refractive index of a translucent resin material such as an epoxy resin satisfies this total reflection condition.

The laser beam totally reflected by the reflecting surface 13 is again totally reflected by the reflecting surface 15 and travels toward the substrate 30. The laser light enters the lens surface 24 after passing through the internal space 61 from the lower surface 18 of the top plate portion 11. The laser light is condensed on the light receiving surface of the light receiving element 32 by the lens surface 24. The light receiving element 32 converts an optical signal from the laser light into a current signal and outputs the current signal. The integrated circuit chip 34 generates a voltage signal by impedance-converting and amplifying the current signal output from the light receiving element 32.

As described above, an output signal corresponding to the input signal is generated by the photocoupler 1.
[Photocoupler manufacturing method]
FIG. 5 is a flowchart showing an example of a manufacturing method of the photocoupler shown in FIGS.

Referring to FIGS. 3 and 5, first, light emitting element 31, light receiving element 32, and integrated circuit chips 33 and 34 are manufactured or prepared (step S100), and substrate 30 on which conductive patterns and electrodes are formed is manufactured. Alternatively, it is prepared (step S110). In this case, an assembly of substrates in a state where a large number of substrates 30 in FIG. 3 are connected in a matrix is manufactured.

Next, the light emitting element 31, the light receiving element 32, and the integrated circuit chips 33 and 34 are attached to each substrate 30 by soldering or the like (step S120). The light emitting element 31, the light receiving element 32, and the integrated circuit chips 33 and 34 are connected to a conductive pattern (not shown) on the main surface 301 of the substrate 30 by a bonding wire (not shown).

Next, the sealing portion 20 made of an epoxy resin is formed on the main surface 301 of each substrate 30 by transfer molding using a mold (step S130). By this transfer molding, the hole 21 and the lens surfaces 23 and 24 of FIG. 3 are integrally molded.

Next, the top plate portion 11 made of an epoxy resin is attached to the upper surface 25 of the sealing portion 20 (step S140). Specifically, a state in which a large number of top plate portions 11 are connected in a matrix is manufactured in advance by transfer molding using a mold. The grooves 12 and 14 are also formed in the top plate 11 in advance by this transfer molding.

Thereafter, the assembly of the substrate 30 and the assembly of the top plate portion 11 are cut into individual substrates by dicing, thereby completing the photocoupler 1 (step S150).

[Modification]
Also in the modification shown below, the function similar to the structure of the photocoupler 1 mentioned above can be show | played.

First, in FIG. 1 to FIG. 3, the internal space 61 of the resin member 60 defined by the hole 21 and the lower surface 18 of the top plate portion 11 may communicate with the external space of the resin member 60. For example, only the side surface portion in the Y direction among the side surface portions of the hole portion 21 may be provided, and the side surface portion in the X direction may not be provided. Only the side surface portion is provided, and the side surface portion in the Y direction may not be provided.

The shapes of the sealing portion 20 and the top plate portion 11 shown in FIGS. 1 to 3 are examples and can be arbitrarily changed. For example, the sealing portion 20 may have a substantially rectangular parallelepiped shape, and the lens surfaces 23 and 24 may be formed so as to protrude from the upper surface thereof. In this case, the side surface portion of the hole portion 21 shown in FIGS. 1 to 3 is formed integrally with the top plate portion 11.

The lens surfaces 23 and 24 may be formed on the lower surface 18 of the top plate portion 11. In other words, the surface that defines the internal space 61 of the resin member 60 includes the bottom surface 22 and the top surface 62 that face each other with the internal space 61 interposed therebetween. In this case, the substrate 30 is located on the opposite side of the internal space 61 with the bottom surface 22 interposed therebetween. Each of the lens surfaces 23 and 24 may be formed on either the bottom surface 22 or the top surface 62. In any case, the lens surfaces 23 and 24 are formed so as to protrude into the internal space 61.

The internal space 61 may be divided into two, and the lens surfaces 23 and 24 may be formed in the two internal spaces, respectively. This will be specifically described with reference to FIG.

FIG. 6 is a cross-sectional view of a photocoupler according to a modification of the first embodiment. The resin member 60 of the photocoupler 1A in FIG. 6 has an internal space 61A and an internal space 61B. Each of the internal spaces 61 </ b> A and 61 </ b> B may communicate with the external space of the resin member 60. The surface defining the internal space 61A includes a bottom surface 22A including the lens surface 23 and an upper surface 62A. The surface that defines the internal space 61B includes a bottom surface 22B including the lens surface 24 and an upper surface 62B. Unlike the case of FIG. 6, the lens surface 23 may be provided on the upper surface 62A, and the lens surface 24 may be provided on the upper surface 62B.

[effect]
According to the photocoupler 1 of the present embodiment, by using a semiconductor laser element such as a VCSEL with good directivity for the light emitting element 31, it is possible to reduce the proportion of light flying in an unnecessary direction like a light emitting diode. . Thereby, the power loss of light can be reduced. In addition, by arranging the lens surface 23 above the light emitting element 31 on the transmitting side, the laser light emitted from the light emitting element 31 can be collimated, so that no light loss occurs on the reflecting surface 13. Can be. Furthermore, by arranging the lens surface 24 above the light receiving element 32 on the receiving side, the laser light regularly reflected by the reflecting surface 15 can be efficiently condensed on the light receiving surface of the light receiving element 32. For example, even if a slight shift occurs in the mounting position of the light receiving element 32 on the substrate 30, the laser light can be condensed in the light receiving surface of the light receiving element 32, so that the power loss of light can be reduced.

As described above, reducing the power loss of light is particularly important for high-speed transmission of Gbps order or higher. This is because the higher the signal transmission speed, the lower the receiving sensitivity on the receiving side, and therefore it is required that the light power loss be as small as possible. Furthermore, by arranging the light emitting element 31 and the light receiving element 32 on the substrate 30, it becomes easy to cope with high-speed signal transmission. In the method using the lead frame, power loss due to impedance mismatch becomes large. For example, the transmission loss of high-speed signals can be suppressed by configuring the substrate 30 with an LGA substrate.

In addition, as in the case of the reflecting surfaces 13 and 15 and the lens surfaces 23 and 24 shown in FIGS. 1 to 3, the manufacturing cost can be reduced by forming an optical mirror and lens using a resin member.

<Embodiment 2>
FIG. 7 is a cross-sectional view illustrating a configuration of the photocoupler according to the second embodiment. In FIG. 7, the optical path of the laser beam from the light emitting element to the light receiving element is indicated by a broken line.

The photocoupler 2 in FIG. 7 is characterized in that the angle formed between the reflecting surfaces 13 and 15 and the main surface of the substrate 30 is larger than 45 degrees. In the case of FIG. 7, since the upper surface 17 of the top plate portion 11 and the main surface 301 of the substrate 30 are substantially parallel, the angle θ ₁ formed by the upper surface 17 of the top plate portion 11 and the reflecting surface 13 and the top plate portion The angle θ ₂ formed by the upper surface 17 of 11 and the reflecting surface 15 is greater than 45 degrees.

In the case of the above configuration, the incident angle θi of the laser beam to the reflecting surface 13 and the reflecting angle θr of the laser beam from the reflecting surface 13 are larger than 45 degrees. Accordingly, in the case of FIG. 7, the laser light totally reflected on the reflecting surface 13 can be further totally reflected on the upper surface 17 of the top plate portion 11 and then reach the reflecting surface 15. The laser light totally reflected by the reflection surface 15 reaches the light receiving surface of the light receiving element 32 after passing through the lens surface 24. Since the other points of FIG. 7 are the same as those of FIG. 4, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

Thus, there may be three or more reflecting surfaces of the laser beam, and in this case, the reflecting angle of each reflecting surface may not be 45 degrees as long as it is larger than the critical angle. The plurality of reflecting surfaces are arranged so that each of them reflects the incident light to guide the laser light emitted from the light emitting element 31 to the light receiving element 32. Even with such a configuration of the photocoupler 2, the same effects as those of the first embodiment can be obtained.

<Embodiment 3>
FIG. 8 is a cross-sectional view illustrating a configuration of the photocoupler according to the third embodiment. In FIG. 8, the optical path of the laser beam from the light emitting element to the light receiving element is indicated by a broken line.

The photocoupler 3 in FIG. 8 is characterized in that the angle formed by the reflecting surfaces 13 and 15 and the main surface of the substrate 30 is smaller than 45 degrees. In the case of FIG. 8, since the top surface 17 of the top plate portion 11 and the main surface 301 of the substrate 30 are substantially parallel, the angle θ ₁ formed by the top surface 17 of the top plate portion 11 and the reflecting surface 13 and the top plate portion The angle θ ₂ formed by the upper surface 17 of 11 and the reflecting surface 15 is smaller than 45 degrees. However, as will be described below, the angles θ ₁ and θ ₂ are larger than the critical angle that is the angle at which the incident light is totally reflected on the reflecting surface.

In the case of the above configuration, the incident angle θi of the laser beam to the reflecting surface 13 and the reflecting angle θr of the laser beam from the reflecting surface 13 are smaller than 45 degrees but larger than the critical angle. Accordingly, in the case of FIG. 8, the laser light totally reflected on the reflecting surface 13 can be further totally reflected on the lower surface 18 of the top plate portion 11 and then reach the reflecting surface 15. The laser light totally reflected by the reflection surface 15 reaches the light receiving surface of the light receiving element 32 after passing through the lens surface 24. Since the other points in FIG. 8 are the same as those in FIG. 4, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

As described above, there may be three or more reflecting surfaces of the laser beam. In this case, the reflecting angle of each reflecting surface may be smaller than 45 degrees as long as it is larger than the critical angle. The plurality of reflecting surfaces are arranged so that each of them reflects the incident light to guide the laser light emitted from the light emitting element 31 to the light receiving element 32. Even with such a configuration of the photocoupler 3, the same effects as in the first embodiment can be obtained.

<Embodiment 4>
FIG. 9 is a cross-sectional view showing the configuration of the photocoupler according to the fourth embodiment. In FIG. 9, the optical path of the laser beam from the light emitting element to the light receiving element is indicated by a broken line. In the photocoupler 4 of FIG. 9, the resin member 60 does not have the internal space 61, and therefore differs from the resin member 60 of FIG. 4 in that it does not have the lens surfaces 23 and 24.

More specifically, the photocoupler 4 includes a sealing portion 20 formed of a translucent resin material that transmits laser light. The sealing unit 20 is formed so as to cover the main surface 301 of the substrate 30, and seals the light emitting element 31, the light receiving element 32, and the integrated circuit chips 33 and 34. The sealing unit 20 has grooves 26 and 28 that are recessed in a direction from the upper surface 25 on the opposite side of the substrate 30 toward the substrate 30. The plane that defines the groove 26 has a flat reflecting surface 27 that regularly reflects the laser beam. Similarly, the plane that defines the groove 26 has a flat reflecting surface 29 that regularly reflects the laser beam.

The reflection surface 27 forms an angle of 45 degrees with respect to the main surface 301 of the substrate 30. The reflection surface 29 forms an angle of 45 degrees with respect to the main surface 301 of the substrate 30 and forms an angle of 90 degrees with respect to the reflection surface 27. In the case of FIG. 3, since the upper surface 25 of the sealing part 20 and the main surface 301 of the substrate 30 are substantially parallel, the angle θ ₁ formed by the upper surface 25 of the sealing part 20 and the reflecting surface 27 is 45 degrees. The angle θ ₂ formed by the upper surface 25 of the sealing portion 20 and the reflecting surface 29 is 45 degrees. Further, the distance from the reflecting surface 27 to the main surface 301 of the substrate 30 is substantially equal to the distance from the reflecting surface 29 to the main surface 301 of the substrate 30. Further, when viewed from the direction perpendicular to the main surface 301 of the substrate 30, the reflective surface 27 and the light emitting element 31 overlap, and the reflective surface 29 and the light receiving element 32 overlap. 9 is the same as that of FIG. 4, and the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

According to the above configuration, the light emitting element 31 emits laser light in a direction perpendicular to the substrate 30. The laser light reaches the reflection surface 29 after being totally reflected by the reflection surface 27. The laser light totally reflected by the reflecting surface 29 reaches the light receiving surface of the light receiving element 32. As a result, basically the same effects as those of the first embodiment are obtained. However, since the laser light emitted from the light emitting element 31 is not necessarily a parallel light beam but has a spread, the laser light gradually increases in beam diameter. In this case, power loss of light can be suppressed by preventing the laser light from protruding from the reflecting surfaces 27 and 29 and the light receiving surface of the light receiving element 32.

It should be noted that the spread of the laser beam can be suppressed by forming the reflecting surfaces 27 and 29 into a curved surface so as to function as a concave mirror.

<Embodiment 5>
FIG. 10 is a cross-sectional view illustrating a configuration of the photocoupler according to the fifth embodiment. In FIG. 10, the optical path of the laser beam from the light emitting element to the light receiving element is indicated by a broken line. The photocoupler 5 in FIG. 10 differs from the photocoupler 1 in FIG. 3 in that a reflecting plate 43 is provided on the upper surface 62 of the internal space 61 instead of the reflecting surfaces 13 and 15 provided on the upper surface of the resin member 60. Different. This will be specifically described below.

Referring to FIG. 10, the resin member 60 is formed of a translucent resin material that transmits laser light, and the outer shape thereof is a substantially rectangular parallelepiped shape. The resin member 60 includes a sealing portion 20 and a top plate portion 40. The sealing unit 20 is formed so as to cover the main surface 301 of the substrate 30 and has an internal space 61 defined by the hole 21.

The specific configuration of the sealing portion 20 is almost the same as that in FIG. 4 of the first embodiment, but the arrangement of the lens surface 23 is different from that in FIG. Specifically, as shown in FIG. 10, the optical axis of the lens surface 23 is shifted from the center of the emission surface of the light emitting element 31 when viewed from the direction perpendicular to the main surface 301 of the substrate 30.

The top plate part 40 is provided so as to cover the hole part 21. The reflection plate 43 is provided on the lower surface 42 of the top plate portion 40 (that is, the upper surface 62 of the internal space 61). The reflecting surface of the reflecting plate 43 (that is, the surface on the substrate 30 side) totally reflects incident light. Light hardly penetrates into the reflection plate 43.

Here, since the optical axis of the lens surface 23 is shifted from the central axis of the emission surface of the light emitting element 31, the laser light emitted from the light emitting element 31 is refracted by the lens surface 23 and guided to the reflecting plate 43. . The laser light regularly reflected by the reflecting surface of the reflecting plate 43 is refracted by the lens surface 24 and collected on the light receiving surface of the light receiving element 32.

Since other points in FIG. 10 are the same as those in FIG. 4, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated. According to the configuration of the photocoupler 5 in FIG. 11 described above, similarly to the case of the first embodiment, it is possible to reduce the power loss of light, thereby enabling signal transmission in the Gbps order.

<Embodiment 6>
FIG. 11 is a cross-sectional view illustrating a configuration of the photocoupler according to the sixth embodiment. In FIG. 11, the optical path of the laser beam from the light emitting element to the light receiving element is indicated by a broken line.

11 differs from the photocoupler 1 of FIG. 4 in that only the transmission-side lens surface 23 is provided and the hour-reception-side lens surface 24 is not provided. Furthermore, the photocoupler 6 in FIG. 11 differs from the photocoupler 1 in FIG. 4 in that a reflecting plate 54 is provided instead of the reflecting surfaces 13 and 15 provided in the resin member 60. The laser light is reflected at the interface between the reflecting plate 54 and the resin member 60. This will be specifically described below.

Referring to FIG. 11, resin member 60 is formed of a translucent resin material that transmits laser light, and includes sealing portion 20 and top plate portion 50. The sealing unit 20 is formed so as to cover the main surface 301 of the substrate 30, and seals the light emitting element 31, the light receiving element 32, and the integrated circuit chips 33 and 34. A hole 21 is formed in the upper surface 25 of the sealing portion 20. The bottom surface 22 of the hole 21 includes a lens surface 23 protruding upward.

The top plate part 11 is attached to the upper surface 25 of the sealing part 20 so as to cover the hole part 21. A curved surface 53 is formed on the surface 51 of the top plate 11 opposite to the substrate 30. A reflection plate 54 is provided so as to cover the curved surface 53. When viewed from a direction perpendicular to the main surface 301 of the substrate 30, the reflecting plate 54, the lens surface 23, and the light emitting element 31 are in a position overlapping each other. It is desirable that the optical axis of the lens surface 23 passes through the center of the emission surface of the light emitting element 31.

The laser beam is reflected at the interface between the reflecting plate 54 and the resin member 60. By forming the reflection plate 54 along the curved surface 53, the reflection plate 54 functions as a concave mirror. As a result, the laser light regularly reflected by the reflecting plate 54 is condensed on the light receiving surface of the light receiving element 32.

Since other points in FIG. 11 are the same as those in FIG. 4, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated. According to the configuration of the photocoupler 6 in FIG. 11 described above, similarly to the case of the first embodiment, it is possible to reduce the power loss of light, thereby enabling signal transmission in the Gbps order.

<Embodiment 7>
FIG. 12 is a cross-sectional view illustrating a configuration of the photocoupler according to the seventh embodiment. In FIG. 12, the optical path of the laser beam from the light emitting element to the light receiving element is indicated by a broken line.

12 is different from the photocoupler 1 in FIG. 4 in that the substrate 30 is separated into a first substrate 30A and a second substrate 30B. In the configuration of FIG. 12, the light emitting element 31 and the integrated circuit chip 33 are disposed on the main surface 301A of the first substrate 30A, and the light receiving element 32, the integrated circuit chip 34, and the main surface 301B of the second substrate 30B. Is placed. The first substrate 30A and the second substrate 30B are arranged along the same plane.

The resin member 60 is formed of a translucent resin material that transmits laser light, and includes a first sealing portion 20A, a second sealing portion 20B, and the top plate portion 11. The first sealing unit 20A seals the light emitting element 31 and the integrated circuit chip 33 by covering the main surface 301A of the first substrate 30A. The second sealing unit 20B seals the light receiving element 32 and the integrated circuit chip 34 by covering the main surface 301B of the second substrate 30B. The top plate portion 11 connects the upper surface 25A of the first sealing portion 20A and the upper surface 25B of the second sealing portion 20B.

The top plate 11 includes a groove 12 that is recessed in the direction from the upper surface 17 opposite to the first substrate 30A toward the first substrate 30A, and the second substrate 30B from the upper surface 17 opposite to the second substrate 30B. And a groove 14 that is recessed in the direction toward the. The plane that defines the groove 12 has a flat reflecting surface 13 that regularly reflects the laser beam. Similarly, the plane that defines the groove 14 has a flat reflecting surface 15 that regularly reflects the laser beam. The reflective surface 13 forms an angle of 45 degrees with respect to the main surface 301A of the first substrate 30A. The reflection surface 15 forms an angle of 45 degrees with respect to the main surface 301B of the second substrate 30B and forms an angle of 90 degrees with respect to the reflection surface 13. The distance from the reflective surface 13 to the main surface 301A of the first substrate 30A is substantially equal to the distance from the reflective surface 15 to the main surface 301B of the second substrate 30B.

The first sealing portion 20A has a first internal space 61A defined by the hole portion 21A. The bottom surface 22A of the hole 21A includes a first lens surface 23 protruding into the first internal space 61A. The second sealing portion 20B has a second internal space 61B defined by the hole portion 21B. The bottom surface 22B of the hole portion 21B includes a second lens surface 24 protruding into the second internal space 61B.

When viewed from the direction perpendicular to the main surface 301A of the first substrate 30A, the reflecting surface 13, the lens surface 23, and the light emitting element 31 overlap, and the lens surface 23 is located between the reflecting surface 13 and the light emitting element 31. ing. It is desirable that the optical axis of the lens surface 23 passes through the center of the emission surface of the light emitting element 31. Similarly, when viewed from the direction perpendicular to the main surface 301B of the second substrate 30B, the reflecting surface 15, the lens surface 24, and the light receiving element 32 overlap, and the lens surface 24 is located between the reflecting surface 15 and the light receiving element 32. Is located. It is desirable that the optical axis of the lens surface 24 passes through the center of the light receiving surface of the light receiving element 32.

According to the photocoupler 7 having the above configuration, the same effects as those of the photocoupler 1 of the first embodiment are obtained. Further, the photocoupler 7 having the above-described configuration is required to increase the distance between the transmission-side terminal and the reception-side terminal of the photocoupler 7 in order to improve the dielectric strength according to the standard, such as a medical device. Is preferably used.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1, 1A, 2-7 photocoupler, 11, 40, 50 top plate part, 12, 14, 26, 28 groove part, 13, 15, 27, 29 reflective surface, 20 sealing part, 20A first sealing part , 20B second sealing part, 21, 21A, 21B hole part, 23, 24 lens surface, 30, 30A, 30B substrate, 31 light emitting element, 32 light receiving element, 33, 34 integrated circuit chip, 35, 37 ground terminal 36, 38 terminal, 43, 54 reflector, 60 resin member, 61, 61A, 61B internal space, 70 optical path, 301, 301A, 301B main surface, 302 back surface.

Claims (18)

A substrate,
A light emitting element disposed on the main surface of the substrate and emitting laser light;
A light receiving element disposed on the main surface of the substrate;
A translucent resin member that seals the light emitting element and the light receiving element by covering the main surface of the substrate;
One or more mirrors disposed on the surface of the resin member,
The one or more mirrors guide the laser light emitted from the light emitting element to the light receiving surface of the light receiving element by each of the one mirror or the plurality of mirrors regularly reflecting incident light. Arranged photocoupler. The surface of the resin member includes one or more reflecting surfaces that function as the one or more mirrors,
2. The photocoupler according to claim 1, wherein an incident angle of the laser light to each of the reflection surfaces is larger than a critical angle that is an angle at which the incident light is totally reflected. The one or more reflective surfaces include a first reflective surface and a second reflective surface;
The first reflective surface forms an angle of 45 degrees with the main surface of the substrate;
The second reflective surface forms an angle of 90 degrees with the first reflective surface;
The light emitting element emits laser light toward the first reflecting surface,
The laser light regularly reflected by the first reflecting surface reaches the second reflecting surface,
The photocoupler according to claim 2, wherein the laser light regularly reflected by the second reflecting surface reaches the light receiving surface of the light receiving element. The resin member has a first groove and a second groove that are recessed from the surface opposite to the substrate toward the substrate,
The surface defining the first groove includes the first reflective surface,
The photocoupler according to claim 3, wherein a surface defining the second groove includes the second reflecting surface. The said 1 or several mirror contains the reflecting plate arrange | positioned on the surface of the said resin member, and a laser beam is regularly reflected in the interface of the said resin member and the said reflecting plate. Photo coupler. The resin member has a first internal space,
The surface defining the first internal space includes a first lens surface protruding into the first internal space,
The laser light emitted from the light emitting element reaches one of the one mirror or the plurality of mirrors after passing through the first lens surface. Photo coupler. A surface defining the first internal space includes a second lens surface protruding into the first internal space;
The photocoupler according to claim 6, wherein the laser light regularly reflected by either the one mirror or the plurality of mirrors reaches the light receiving surface of the light receiving element after passing through the second lens surface. The photocoupler according to claim 7, wherein the substrate is located on the opposite side of the first internal space with the first lens surface and the second lens surface interposed therebetween. The resin member further has a second internal space different from the first internal space,
A surface defining the second internal space includes a second lens surface protruding into the second internal space;
The photocoupler according to claim 6, wherein the laser light regularly reflected by either the one mirror or the plurality of mirrors reaches the light receiving surface of the light receiving element after passing through the second lens surface. The resin member has an internal space,
The surface defining the internal space includes a bottom surface and an upper surface facing each other with the internal space in between,
The substrate is located on the opposite side of the internal space with the bottom surface in between,
The one or more mirrors include a reflector disposed on the top surface;
The bottom surface is
A first lens surface for guiding laser light emitted from the light emitting element to the reflector;
The photocoupler according to claim 1, further comprising: a second lens surface that guides the laser light regularly reflected by the reflecting plate to the light receiving surface of the light receiving element. 11. The photocoupler according to claim 1, wherein the light emitting element includes a vertical cavity surface emitting laser element. The photocoupler according to any one of claims 1 to 11, further comprising a first integrated circuit chip disposed on the main surface of the substrate and supplying a drive signal to the light emitting element. The photocoupler according to any one of claims 1 to 12, further comprising a second integrated circuit chip disposed on the main surface of the substrate and processing an output signal of the light receiving element. A first ground terminal for the light emitting element disposed on a back surface opposite to the main surface of the substrate;
The second ground terminal for the light receiving element that is disposed on the back surface of the substrate and is electrically separated from the first ground terminal. Photocoupler. The substrate is separated into a first substrate and a second substrate;
The light emitting element is disposed on a main surface of the first substrate;
The light receiving element is disposed on a main surface of the second substrate;
The resin member is
A first sealing portion that seals the light emitting element by covering the main surface of the first substrate;
A second sealing portion for sealing the light receiving element by covering the main surface of the second substrate;
A top plate portion that connects the surface of the first sealing portion opposite to the first substrate and the surface of the second sealing portion opposite to the second substrate;
The surface of the top plate includes one or more reflecting surfaces that function as the one or more mirrors,
2. The photocoupler according to claim 1, wherein an incident angle of the laser light to each of the reflection surfaces is larger than a critical angle that is an angle at which the incident light is totally reflected. The first sealing portion has a first internal space,
The surface defining the first internal space includes a first lens surface protruding into the first internal space,
After the laser light emitted from the light emitting element passes through the first lens surface, it reaches one of the one reflecting surface or the plurality of reflecting surfaces,
The second sealing portion has a second internal space,
A surface defining the second internal space includes a second lens surface protruding into the second internal space;
The photo beam according to claim 15, wherein the laser light regularly reflected by either the one reflecting surface or the plurality of reflecting surfaces reaches the light receiving surface of the light receiving element after passing through the second lens surface. Coupler. A substrate,
A light emitting element disposed on the main surface of the substrate and emitting laser light in a direction perpendicular to the substrate;
A light receiving element located on the main surface of the substrate;
A translucent resin member for sealing the light emitting element and the light receiving element by covering the main surface of the substrate;
The resin member has a refractive index greater than √2,
The surface of the resin member includes a first reflecting surface and a second reflecting surface that regularly reflect incident light,
The first reflecting surface forms an angle of 45 degrees with the main surface of the substrate and is disposed at a position overlapping the light emitting element when viewed from a direction perpendicular to the substrate,
The second reflecting surface forms an angle of 90 degrees with the first reflecting surface, faces the first reflecting surface with a part of the resin member interposed therebetween, and is perpendicular to the substrate. A photocoupler disposed at a position overlapping the light receiving surface of the light receiving element when viewed from the direction. The resin member has an internal space,
The surface defining the internal space includes a bottom surface and an upper surface facing each other with the internal space in between,
The substrate is located on the opposite side of the internal space with the bottom surface in between,
The bottom surface is
A first lens surface located between the light emitting element and the first reflecting surface and protruding into the internal space;
The photocoupler according to claim 17, further comprising: a second lens surface that is located between the light emitting element and the second reflecting surface and protrudes into the internal space.

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