Optical coupler with a side-emitting electromagnetic radiation source

Abstract

An optical coupler (100) includes a side-emitting electromagnetic radiation source (102) for emitting electromagnetic radiation at its side wall (104), and an electromagnetic radiation detector (106) for detecting at least a portion of the emitted electromagnetic radiation.

Description

Technical Field

[0001] The present invention relates to an optical coupler and a method of operating an optical coupler. Background Art

[0002] An optical coupler can be an electronic component that transfers an electrical signal between two isolated circuits by using light. For example, an optical coupler can prevent high voltages from affecting a system that receives the signal. A common type of optical coupler can include a light-emitting diode and a phototransistor within the same opaque package.

[0003] There is still potential room to improve the optical coupling of an optical coupler. Summary of the Invention

[0004] There may be a need for an optical coupler with improved optical coupling.

[0005] According to an exemplary embodiment, there is provided an optical coupler that includes a side-emitting electromagnetic radiation source for emitting electromagnetic radiation at its sidewall, and an electromagnetic radiation detector for detecting at least a portion of the emitted electromagnetic radiation.

[0006] According to another exemplary embodiment, there is provided a method of operating an optical coupler, the method including emitting electromagnetic radiation at a sidewall of a side-emitting electromagnetic radiation source, and detecting at least a portion of the emitted electromagnetic radiation by an electromagnetic radiation detector.

[0007] According to an exemplary embodiment, there is provided an optical coupler having an electromagnetic radiation source that radiates electromagnetic radiation (e.g., light) mainly or entirely via its side. Thus, the side-emitting electromagnetic radiation source can emit electromagnetic radiation to propagate substantially horizontally, rather than via a top or bottom main surface. As a result, improved optical coupling can be obtained between such a side-emitting electromagnetic radiation source and an electromagnetic radiation detector arranged side by side with the electromagnetic radiation source, because this geometry and configuration enable direct transmission of electromagnetic radiation along a short propagation path. Contrary to conventional methods, the electromagnetic radiation beam can thus propagate mainly horizontally through the optical coupler on its way from the electromagnetic radiation source to the electromagnetic radiation detector. Therefore, the improved optical coupling between the electromagnetic radiation source and the electromagnetic radiation detector can enable more reliable and more fault-robust operation of the optical coupler. The latter can be implemented as a switching solid-state relay, for example.

[0008] Description of Other Exemplary Embodiments

[0009] Below, other exemplary embodiments of the optical coupler and the method will be explained.

[0010] In the context of the present application, the term "optical coupler" may particularly denote an optoelectronic component that couples two conductive but electrically isolated circuits to each other via an optical link provided by a beam of electromagnetic radiation (e.g., a light beam). Such optical coupling can be provided between an electromagnetic radiation source and an electromagnetic radiation detector that are separated or electrolytically decoupled from the electromagnetic radiation detector current.

[0011] In the context of the present application, the term "electromagnetic radiation source" may particularly denote a component capable of generating and (especially in a directional manner) emitting a beam of electromagnetic radiation. According to an exemplary embodiment, the electromagnetic radiation source may be configured to emit a beam of electromagnetic radiation that propagates along an approximately horizontal rather than a vertical direction. For example, the emitted beam of electromagnetic radiation may be a light beam, and more particularly, a visible light beam. The electromagnetic radiation source may convert an electrical signal to be transmitted to the electromagnetic radiation detector side into an optical signal for transmission via the optical link.

[0012] In the context of the present application, the term "electromagnetic radiation detector" may particularly denote an electronic component capable of detecting electromagnetic radiation (e.g., light) received from an electromagnetic radiation source and converting the signal associated with the transmitted electromagnetic radiation into an electrical signal for further processing on the detector side. For example, the electromagnetic radiation detector may be configured to detect electromagnetic radiation within a limited bandwidth (i.e., within a limited wavelength range). The emission characteristics of the electromagnetic radiation source and the detection characteristics of the electromagnetic radiation detector may be adjusted to match.

[0013] In the context of the present application, the term "side-emitting" electromagnetic radiation source may particularly denote that the surface of the electromagnetic radiation source that emits electromagnetic radiation (e.g., visible light) is a (especially vertically oriented) side wall rather than a (e.g., horizontally oriented) main surface. For example, such an electromagnetic radiation source may be a plate-shaped element or a cuboid element that emits light along a relatively small side wall rather than along a larger top surface or bottom surface. When the side-emitting electromagnetic radiation source is a laser diode, the electromagnetic radiation inside the laser diode may propagate in a laser resonator between an ideal mirror and a deliberately non-ideal mirror. Both the ideal mirror and the non-ideal mirror may be formed by the respective side walls of the laser diode. For example, compared with the ideal mirror, the non-ideal mirror side wall may have a greater roughness and thus deliberately reduce the reflection ability. The electromagnetic radiation propagating between the two side walls may then be emitted mainly or even solely via the non-ideal mirror side wall.

[0014] In an embodiment, the electromagnetic radiation source is a laser diode. For example, such a laser diode can be manufactured using semiconductor technology, in particular silicon technology or gallium arsenide technology. The laser diode can be powered by an electric current and can generate electromagnetic radiation at the pn junction, which can be emitted via the side surface of the laser diode. By taking this measure, an electromagnetic radiation beam with a specific orientation can be emitted for propagation towards the electromagnetic radiation detector for detection.

[0015] As an alternative to the laser diode, the side-emitting electromagnetic radiation source can be implemented according to DLP (Digital Light Processing) technology (e.g., implementing micromirrors).

[0016] In an embodiment, the electromagnetic radiation detector is a photodiode. The photodiode can be an optical element having a pn junction, and this optical element is capable of capturing electromagnetic radiation to convert it into charge and thus into voltage or current. For example, the photosensitive surface of the photodiode (especially plate-shaped or cuboid) can be its upper main surface or lower main surface. Thus, a large detection surface is provided by the photodiode.

[0017] In an embodiment, the electromagnetic radiation source and the electromagnetic radiation detector are current-separated. In the context of the present application, the term "current-separated" can particularly mean that the electromagnetic radiation source and the electromagnetic radiation detector are electrolytically decoupled from each other such that no electrical signal can directly propagate from the electromagnetic radiation source to the electromagnetic radiation detector. Thus, the communication between the two current-separated parts of the optical coupler is provided by the optical link between the electromagnetic radiation source and the electromagnetic radiation detector. This optical path can bridge the circuit paths separated from each other on one side of the electromagnetic radiation source and on one side of the electromagnetic radiation detector.

[0018] In an embodiment, the electromagnetic radiation source is configured to emit electromagnetic radiation only at its sidewalls and not at or substantially not at any of its main surfaces. By triggering the emission of electromagnetic radiation to occur only via the sidewalls of the electromagnetic radiation source, a clear and directional transmission of electromagnetic radiation can be achieved. This results in a high transmission efficiency of the optical coupler.

[0019] In an embodiment, the electromagnetic radiation detector is configured to detect electromagnetic radiation at one of its main surfaces, especially only at one of its main surfaces. This can be accomplished by forming the pn junction of the photodiode-type electromagnetic radiation detector close to its upper main surface. By using the large main surface of the electromagnetic radiation detector for detection purposes, a high detection efficiency can be achieved.

[0020] In an embodiment, the optical coupler includes a control unit that is coupled to the electromagnetic radiation detector and is configured to perform a control task (in particular, perform a switching task) or to perform control (in particular, perform switching) based on the detected electromagnetic radiation. For example, such a control unit can be one or more semiconductor chips and / or any other circuitry. The control unit can also include software elements. The control unit can be provided with the signal detected by the electromagnetic radiation detector. The control unit can then further process such a signal in order to recover the electrical signal transmitted from the electromagnetic radiation source in the form of electromagnetic radiation.

[0021] In an embodiment, the optical coupler includes an optically transparent encapsulation, in particular including a transparent gel, in which at least a part of the electromagnetic radiation source and at least a part of the electromagnetic radiation detector are embedded, in particular embedded in the transparent gel. Such an optically transparent encapsulation can be optically transparent in the wavelength range of the electromagnetic radiation propagating between the electromagnetic radiation source and the electromagnetic radiation detector. In context, electrically transparent can denote a property of the encapsulation according to which the encapsulation substantially does not absorb the electromagnetic radiation transmitted between the electromagnetic radiation source and the electromagnetic radiation detector. For example, the encapsulation can be a transparent gel through which visible light can propagate with low loss or low attenuation.

[0022] In an embodiment, the optical coupler includes a housing that encloses at least a part of the electromagnetic radiation source and at least a part of the electromagnetic radiation detector and has a reflective inner surface that is configured to reflect at least a part of the electromagnetic radiation emitted by the electromagnetic radiation source (in particular, to totally reflect the electromagnetic radiation). For example, at the inner boundary surface of the housing (which can correspond to the outer boundary surface of the encapsulation), the electromagnetic radiation propagating from the electromagnetic radiation source and away from the electromagnetic radiation detector can be reflected and can thus be promoted to propagate towards the electromagnetic radiation detector. Therefore, the efficiency of light transmission can be further improved. For example, at least a part of the housing can be opaque so as to prohibit or at least inhibit ambient light from undesirably propagating to the electromagnetic radiation detector.

[0023] In an embodiment, the inner reflective surface of the housing (which can correspond to the outer surface of the optically transparent encapsulation) is configured to reflect and direct at least a part of the electromagnetic radiation onto the electromagnetic radiation detector. In particular, a curved (e.g., elliptical curved) reflective surface can be configured in such a way that it focuses the electromagnetic radiation onto the photosensitive surface of the electromagnetic radiation detector. This can further improve the efficiency of optical coupling.

[0024] In an embodiment, the electromagnetic radiation source is configured to emit red light, in particular only red light. When using an electromagnetic radiation source that emits within the red light range (i.e., approximately 600 nm), relatively simple components can be used for the electromagnetic radiation source and the electromagnetic radiation detector, and the undesired losses due to scattering can be kept small.

[0025] In an embodiment, the optical coupler includes a source carrier on which the electromagnetic radiation source is mounted. Additionally, the optical coupler can include a detector carrier on which the electromagnetic radiation detector is mounted. The carriers can be conductive. For example, the carriers can be lead frames, such as made of copper. Alternatively, other kinds of carriers can be used, such as carriers having electrically insulating and thermally conductive layers (e.g., ceramics) covered with corresponding copper foils on two opposite main surfaces thereof. For example, a direct copper bonding (DCB) substrate or a direct aluminum bonding (DAB) substrate can be used. The source carrier and the detector carrier can be electrically separated or galvanically decoupled from each other. By taking such measures, a direct electrical connection between the electromagnetic radiation source and the electromagnetic radiation detector and the assigned circuit portions can be prevented, and a bridge therebetween can be provided via an optical link.

[0026] In one embodiment, the source carrier and the detector carrier can be separate carriers. In another embodiment, the source carrier and the detector carrier can be different parts of a common carrier. For example, the source carrier and the detector carrier are lead frames or separate parts of a common lead frame. When implemented as one or two lead frames, the carriers can be provided with less force and can simultaneously perform a mechanical support function and an electrical function. In this case, at least one carrier can transmit an electrical signal that is converted into an optical signal at the optical interface between the electromagnetic radiation source and the electromagnetic radiation detector.

[0027] In an embodiment, the source carrier and the detector carrier are plate-shaped planar structures. This allows the optical coupler to be manufactured in a vertically compact manner.

[0028] In an embodiment, the source carrier and the detector carrier are arranged at the same vertical level. When arranged at the same level, the electromagnetic propagation path can be made very short.

[0029] In an embodiment, the source carrier is arranged at a higher vertical level than the detector carrier, such that the light-emitting sidewall is arranged at a higher vertical level than the sidewall of the electromagnetic radiation detector. When the electromagnetic beam is emitted via the sidewall of the electromagnetic radiation source and detected at the top-side main surface of the electromagnetic radiation detector, for an effective optical link, it can be preferable to arrange the electromagnetic radiation detector at a lower vertical level than the electromagnetic radiation source. This can make the light transmission more effective.

[0030] In an embodiment, at least a portion of at least one of the source carrier and the detector carrier is skewed such that the electromagnetic radiation source and the electromagnetic radiation detector are inclined relative to each other. Preferably, a portion of the detector carrier may be skewed relative to the remaining planar portion of the detector carrier and relative to the source carrier. In such a configuration, the electromagnetic radiation propagating from the sidewall of the electromagnetic radiation source efficiently impinges on the photosensitive surface of the electromagnetic radiation detector that is skewed relative to the horizontal direction. This makes the transmission of the optical signal more efficient. For example, tilting a portion of the detector carrier can be achieved by bending the corresponding portion of the lead frame.

[0031] In an embodiment, the optical coupler includes a deflector that is arranged to deflect at least a portion of the emitted electromagnetic radiation onto the electromagnetic radiation detector. Such a deflector can deflect the electromagnetic radiation that propagates from the electromagnetic radiation source to the electromagnetic radiation detector but does not reach the photosensitive surface of the electromagnetic radiation detector. By deflecting such light back onto the photosensitive surface of the electromagnetic radiation detector, the efficiency of the light transmission is further improved.

[0032] In an embodiment, the deflector is mounted on the detector carrier on which the electromagnetic radiation detector is also mounted. Thus, no additional mounting base is required for the deflector, which makes the optical coupler compact and lightweight.

[0033] In an embodiment, the electromagnetic radiation detector is arranged between the electromagnetic radiation source and the deflector. For example, the electromagnetic radiation source, the electromagnetic radiation detector, and the deflector may be arranged along a substantially longitudinal path such that the electromagnetic radiation that has missed the detection surface of the electromagnetic radiation detector can be deflected by the deflector back onto the detection surface.

[0034] In an embodiment, the deflector has a deflection surface that is angled with the incident electromagnetic radiation emitted by the electromagnetic radiation source and deflected onto the electromagnetic radiation detector at a deflection angle within the range between 30° and 60°, particularly at a deflection angle of approximately 45°. It has been shown that with the mentioned deflection angle, the electromagnetic radiation can be effectively deflected onto the detection surface of the electromagnetic radiation detector.

[0035] In an embodiment, the deflector comprises a weldable material (e.g., a metallic material such as copper) or is made of a weldable material. In particular, the deflector can be welded to the detector carrier (e.g., a lead frame portion made of copper) on which the electromagnetic radiation detector is mounted. Thus, the deflector can be welded to the detector carrier, such as a lead frame.

[0036] In an embodiment, the optical coupler is configured as a relay, in particular a solid-state relay. The optical coupler can thus be integrated in a solid-state switch, which allows the implementation of switching performance in a circuit. The switching can be implemented based on an optical signal sent from an electromagnetic radiation source to an electromagnetic radiation detector, without current coupling therebetween.

[0037] In an embodiment, the electromagnetic radiation source is configured to emit at least 60%, in particular at least 80%, of the total intensity of electromagnetic radiation in an angular range not greater than 45°, in particular not greater than 30°, around an axis perpendicular to the sidewall at its sidewall. With this configuration, a major part of the intensity of the emitted electromagnetic radiation can be concentrated within a narrow cone having an axis perpendicular to the sidewall (e.g., a vertical plane). Thus, an efficient transfer of electromagnetic radiation from the sidewall-emitting electromagnetic radiation source to the electromagnetic radiation detector can be achieved.

[0038] In an embodiment, the sidewall-emitting electromagnetic radiation source is configured to emit substantially monochromatic electromagnetic radiation. Correspondingly, the electromagnetic radiation detector can be configured to detect substantially only the substantially monochromatic electromagnetic radiation (i.e., be particularly sensitive to the wavelength). As a substantially monochromatic light source configured for sidewall emission, an appropriate laser diode can be implemented. In particular, when the sidewall-emitting electromagnetic radiation source is configured as a laser diode, it will emit a very narrow bandwidth, which is substantially monochromatic. Very advantageously, the electromagnetic radiation detector can be matched to the substantially monochromatic electromagnetic radiation emitted by the sidewall-emitting electromagnetic radiation source in terms of its detection sensitivity. For example, the bandgap of the semiconductor material of the electromagnetic radiation detector (e.g., a photodiode) can be adjusted such that the bandgap is suitable for the emitted monochromatic electromagnetic radiation. By taking this measure, the signal-to-noise ratio can be reduced, the detection efficiency can be increased, and the suppression of non-specific ambient light and underground signals can be facilitated. As a result, an efficient optical coupler is obtained.

[0039] Preferably, the electromagnetic radiation detector is configured to detect electromagnetic radiation only at the upper main surface of the electromagnetic radiation detector. In particular, the electromagnetic radiation detector can be configured as a photodiode having its pn junction at the upper main surface. Thus, so far, the detection efficiency is maximum in this upper main surface of the electromagnetic radiation detector. Therefore, the mutual orientation between the sidewall-emitting electromagnetic radiation source and the electromagnetic radiation detector can be adjusted to achieve an appropriate efficiency of transmitting light and thus information.

[0040] As the substrate or wafer on which the implemented electronic chip is based, a semiconductor substrate, preferably a silicon substrate, can be used. Alternatively, a silicon oxide or another insulator substrate can be provided. A germanium substrate or a III-V semiconductor material can also be implemented. For example, the exemplary embodiments can be implemented in GaN or SiC technology.

[0041] In addition, exemplary embodiments may utilize standard semiconductor process technologies, such as suitable etching techniques (including isotropic and anisotropic etching techniques, particularly including plasma etching, dry etching, wet etching), patterning techniques (which may involve photolithography masks), deposition techniques (such as chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), sputtering, etc.).

[0042] In conjunction with the accompanying drawings, the above and other objects, features, and advantages of the present invention will become apparent from the following description and the appended claims, in which like parts or elements are denoted by like reference numerals. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The drawings, which are included to provide a further understanding of the exemplary embodiments and constitute a part of this specification, illustrate the exemplary embodiments.

[0044] In the drawings:

[0045] Figure 1 A cross-sectional view of an optical coupler according to an exemplary embodiment is shown.

[0046] Figure 2 A cross-sectional view of an optical coupler according to another exemplary embodiment is shown.

[0047] Figure 3 A cross-sectional view of an optical coupler according to yet another exemplary embodiment is shown.

[0048] Figure 4 A cross-sectional view of an optical coupler according to still another exemplary embodiment is shown.

[0049] Figure 5 A cross-sectional view of an optical coupler according to yet another exemplary embodiment is shown. DETAILED DESCRIPTION

[0050] The illustrations in the drawings are schematic.

[0051] Before further describing other exemplary embodiments in detail, some basic considerations of the inventors will be summarized based on the exemplary embodiments that have been developed.

[0052] According to an exemplary embodiment, an optical coupler (preferably implemented as a solid-state relay) using a side-emission arrangement may be provided. Thus, a side-emitting electromagnetic radiation source (e.g., a laser diode) may be implemented instead of a front-to-front arrangement based on a light-emitting diode (LED). By taking this measure, the exemplary embodiment may provide improved directional light transmission.

[0053] A solid state relay can use one or more optocouplers to provide galvanic isolation of electrical potential. On one side, an emitting device can be provided for emitting light, and on the other side, a photodetector can be provided for detecting the light and reacting to an electrical change of a parameter (such as a resistance) or generating electricity (such as in the presence of a solar cell) to trigger an auxiliary power device that actually switches the solid state relay.

[0054] In all cases, good optical coupling between light generation and light detection can be advantageous because the amount of light detected at the detector can be related to the switching speed.

[0055] Exemplary embodiments provide an architecture that can improve such optical coupling. Instead of a front-emitting LED, such exemplary embodiments can use a side-emitting device, such as a laser diode.

[0056] Exemplary embodiments can provide an optocoupler that has a high-efficiency low-loss coupling between an input side (i.e., a side-emitting electromagnetic radiation source) and an output side (i.e., an electromagnetic radiation detector). Illustratively, the emission characteristics of the side-emitting electromagnetic radiation source can be precisely defined (i.e., at its vertical sidewall) so as to obtain a defined radiation direction. Thus, the electromagnetic radiation detector can be arranged and its photosensitive surface is according to the emission direction of the side-emitting electromagnetic radiation source, so as to obtain an efficient optical coupling between the source side and the detector side. In other words, the radiation path can be directly adjusted from the left side to the right side of the optocoupler. To further improve the transmission efficiency, the electromagnetic radiation detector can be slightly tilted relative to the emission sidewall of the electromagnetic radiation source. The tilt can be, for example, within an angular range between 10° and 50°, particularly within a range between 20° and 40°, preferably about 30°.

[0057] Figure 1 A cross-sectional view of an optocoupler 100 according to an exemplary embodiment is shown. The optocoupler 100 is used as a solid state relay.

[0058] The shown optocoupler 100 includes a side-emitting electromagnetic radiation source 102 for emitting electromagnetic radiation 132 at its sidewall 104. The electromagnetic radiation source 102 can be a laser diode, which is configured to emit substantially monochromatic or at least narrow-bandwidth light, preferably red light. Further preferably, the electromagnetic radiation source 102 can be configured to emit electromagnetic radiation 132 only at its sidewall 104 (i.e., at its vertical surface on the right side) and not at any one of its main surfaces (i.e., the two opposite horizontal surfaces of the electromagnetic radiation source 102 according to Figure 1 or at any of its other sidewalls. Figure 1

[0059] An electromagnetic radiation detector 106 can be provided in the optical coupler 100 for detecting the emitted electromagnetic radiation 132 that has propagated to the photosensitive surface of the electromagnetic radiation detector 106. The electromagnetic radiation detector 106 can be a photodiode having a photosensitive upper main surface. Thus, according to Figure 1 , the electromagnetic radiation detector 106 is configured to detect the electromagnetic radiation 132, for example, only at its upper main surface 108.

[0060] As shown, the side-emitting electromagnetic radiation source 102 and the electromagnetic radiation detector 106 are arranged side by side (instead of vertically stacked) such that the electromagnetic radiation 132 emitted by the electromagnetic radiation source 102 propagates substantially horizontally until it reaches the electromagnetic radiation detector 106.

[0061] The electromagnetic radiation source 102 and the electromagnetic radiation detector 106 are current-separated (i.e., electrically insulated from each other) and are coupled by an optical link provided by the propagating electromagnetic radiation 132.

[0062] Similarly as Figure 1 shown, the optical coupler 100 includes a flat metal source carrier 116 on which the electromagnetic radiation source 102 is mounted (e.g., by soldering or sintering). In addition, a flat metal detector carrier 118 is provided on which the electromagnetic radiation detector 106 is mounted (e.g., by soldering or sintering). The upper main surface of the electromagnetic radiation source 102 is electrically connected to the source carrier 116 by a conductive connection element 134 (e.g., a bonding wire, or a bonding strip, or alternatively a clip). Correspondingly, the upper main surface of the electromagnetic radiation detector 106 is electrically connected to the control unit 110 (described in further detail below) by a conductive connection element 136 (e.g., a bonding wire, or a bonding strip, or alternatively a clip). For example, the source carrier 116 and the detector carrier 118 can be two separate metal carriers (e.g., two lead frames) or can be separate parts of a common metal carrier (e.g., a common lead frame). Such a lead frame can be made of, for example, copper and can be a patterned or stamped metal sheet. The source carrier 116 and the detector carrier 118 can be electrolytically decoupled.

[0063] As already mentioned, the optical coupler 100 also includes a control unit 110 that is coupled to the electromagnetic radiation detector 106 and is configured to perform control tasks (in particular switching tasks) based on the signal content of the detected electromagnetic radiation 132. The control unit 110 can be a semiconductor chip or an arrangement of semiconductor chips and can be electrically coupled to the electromagnetic radiation detector 106 for further processing the detected signal after converting the detected electromagnetic radiation 132 into an electrical signal.

[0064] Similarly as Figure 1As shown, the optical coupler 100 includes an optically transparent encapsulant 112 (e.g., a transparent gel), in which an electromagnetic radiation source 102 and an electromagnetic radiation detector 106 are embedded in such a way that electromagnetic radiation propagates with low loss within the optically transparent encapsulant 112.

[0065] An opaque housing 130 surrounding a portion of the electromagnetic radiation source 102 and a portion of the electromagnetic radiation detector 106 has a reflective inner surface 114, which is configured to reflect (preferably, for total reflection) the electromagnetic radiation 132 emitted by the electromagnetic radiation source 102. The outer surface of the optically transparent encapsulant 112 corresponds to the reflective inner surface 114 of the housing 130, and the outer surface of the optically transparent encapsulant 112 is configured to partially or completely reflect the electromagnetic radiation 132. More specifically, the reflective inner surface 114 may be configured to reflect and direct the electromagnetic radiation 132 onto the electromagnetic radiation detector 106. The housing 130 may be an outer casing or another encapsulant.

[0066] The electromagnetic radiation source 102 implemented as a laser diode can emit narrow-bandwidth light, and the narrow-bandwidth light can be selected according to the absorption characteristics of the transparent gel forming the encapsulant 112, for example, to fit the best possible transmission window. Preferably, red light can be used because this can allow the components of the optical coupler 100 to be implemented with reasonable effort.

[0067] Figure 1 The embodiment shows how the electromagnetic radiation source 102 emits electromagnetic radiation 132 (e.g., visible light in the red wavelength range). In the emitted electromagnetic radiation 132, information to be sent to the electromagnetic radiation detector 106 is included. The corresponding electromagnetic radiation 132 is emitted only via the vertical sidewalls 104 of the plate-shaped electromagnetic radiation source 102. As Figure 1 shown, the propagation path to the photosensitive surface 108 on the upper side of the plate-shaped electromagnetic radiation detector 106 is shorter, and thus the emission efficiency is higher. In addition, the reflection at the curved surface 114 between the optically transparent encapsulant 112 and the housing 130 further increases the amount of electromagnetic radiation 132 propagating to the photosensitive upper main surface 108 of the electromagnetic radiation detector 106. The electrical connection between the source carrier 116 and the electromagnetic radiation source 102 is achieved through a conductive connection element 134. Thus, an electrical signal can be conducted along the source carrier 116 via the conductive connection element 134 to the electromagnetic radiation source 102, where the electrical signal is converted into electromagnetic radiation 132. Then the electromagnetic radiation 132 is sent to the electromagnetic radiation detector 106 for detection. Then, the detected electromagnetic radiation 132 is converted into an electrical signal in the electromagnetic radiation detector 106. Then, the latter electrical signal is forwarded to the control unit 110 via another conductive connection element 136. Alternatively, the detector carrier 118 can also carry the electrical signal.

[0068] Likewise Figure 1 As shown, the electromagnetic radiation source 102 can be configured to provide a Figure 1 The side emitting electromagnetic radiation source 102 emits a major portion of, for example, at least 60% of the intensity of the electromagnetic radiation 132 through its side wall 104 within a narrow angular range α of, for example, 30° extending horizontally and perpendicular to the axis of the side wall 104. By focusing the major portion of the emitted electromagnetic radiation intensity within a narrow cone having an axis perpendicular to the emitting side wall 104, such a configuration can promote efficient transmission of the electromagnetic radiation 132 from the side emitting electromagnetic radiation source 102 to the electromagnetic radiation detector 106.

[0069] Figure 2 A cross-sectional view of an optical coupler 100 according to another exemplary embodiment is shown.

[0070] Figure 2 Examples and Figure 1 The embodiment shown differs in that, according to Figure 2 , the source carrier 116 and the detector carrier 118 are arranged on the same vertical level 120. Since both the source carrier 116 and the detector carrier 118 are on the same vertical level, they can be realized by a common patterned or structured metal plate.

[0071] according to Figure 2 , one lead frame constitutes the source carrier 116 and the detector carrier 118, which are therefore located at the same vertical level, although they are electrically decoupled from each other. Figure 2 A very simple embodiment is shown in FIG, wherein both the emitter (i.e., electromagnetic radiation source 102) and the detector (i.e., electromagnetic radiation detector 106) are located at the same vertical level. This embodiment relies on the diffusion of side emission in the transparent gel forming the optically transparent enclosure 112 in order to illuminate the front side (i.e., photosensitive surface 108) of the electromagnetic radiation detector 106.

[0072] Figure 3 A cross-sectional view of an optical coupler 100 according to yet another exemplary embodiment is shown.

[0073] Figure 3 Examples and Figure 2 The embodiment shown differs in that, according to Figure 3 , the source carrier 116 is arranged at a higher vertical level 120 than the detector carrier 118. As a result, the light emitting side wall 104 is arranged at a higher vertical level than the facing side wall 105 of the electromagnetic radiation detector 106.

[0074] therefore, Figure 3 The source carrier 116 and the detector carrier 118 are shown implemented as two parallel lead frames at different height levels.Figure 3 If it is slightly raised as shown, even better geometric coupling and irradiation capture can be obtained.

[0075] Figure 4 A cross-sectional view of an optical coupler 100 according to yet another exemplary embodiment is shown.

[0076] According to Figure 4 , a portion of the detector carrier 118 is skewed (e.g., by bending a metal plate) such that the electromagnetic radiation source 102 and the electromagnetic radiation detector 106 are inclined relative to each other.

[0077] Illustratively, the source-facing end 107 of the detector carrier 118 is bent to provide a face-to-face lead frame architecture for improving light transmission efficiency. Thus, the advantages achievable with the described side emission can be combined with the shown advantageous inclination of at least one of the elements involved (i.e., the electromagnetic radiation source 102, the electromagnetic radiation detector 106, the source carrier 116, and the detector carrier 118).

[0078] According to Figure 4 The light efficiency in the transmission geometry of is very advantageous because the detector-carrying portion of the detector carrier 118 is skewed. Thus, the electromagnetic radiation detector 106 can be attached or mounted on the detector carrier 118 such that the skewed upper detection surface 108 of the electromagnetic radiation detector 106 is properly oriented relative to the emission sidewall 106 of the electromagnetic radiation source 102. Thus, as shown, the emitted electromagnetic radiation 132 can propagate substantially horizontally from the sidewall 104 to the surface 108.

[0079] Figure 5 A cross-sectional view of an optical coupler 100 according to yet another exemplary embodiment is shown.

[0080] According to Figure 5 The optical coupler 100 of includes a deflector 122 which is arranged to deflect a portion of the emitted electromagnetic radiation 132 onto the electromagnetic radiation detector 106, thereby increasing the portion of the emitted electromagnetic radiation 132 that can be detected on the photosensitive surface 108 of the electromagnetic radiation detector 106. As shown, the deflector 122 is mounted on the detector carrier 118 in a simple manner, on which the electromagnetic radiation detector 106 is also mounted. Thus, the electromagnetic radiation detector 106 is arranged horizontally between the electromagnetic radiation source 102 and the deflector 122. The shown deflector 122 has a deflection surface 166 which is angled at a deflection angle of β = 45° with respect to the portion of the incident electromagnetic radiation 132 to be deflected onto the electromagnetic radiation detector 106. Preferably, the deflector 122 can be made of a weldable material and can be welded to the detector carrier 118 on which the electromagnetic radiation detector 106 is mounted.

[0081] Therefore, Figure 5 A reflector or deflector 122 on the receiving lead frame side is shown. Such a configuration with a laser diode can result in highly directional illumination. A deflector 122 at a 45° angle can be used, which is particularly advantageous for further increasing illumination capture. The deflector material is preferably made of a weldable material and can be attached similar to a clip.

[0082] By arranging the deflector 122 to project vertically outside the electromagnetic radiation detector 106, horizontally propagating light originating from the side wall 104 of the electromagnetic radiation source 102 and propagating horizontally can be effectively deflected onto the photosensitive upper main surface 108 of the electromagnetic radiation detector 106, thereby further improving the optical coupling efficiency.

[0083] It should be noted that the term "comprising" does not exclude other elements or features, and "a" does not exclude a plurality. In addition, elements described in connection with different embodiments can be combined. It should also be noted that reference numerals should not be construed as limiting the scope of the claims. Furthermore, the scope of the present application is not intended to be limited to the specific embodiments of the processes, machines, manufactures, compositions of matter, devices, methods, and steps described in the specification. Therefore, the appended claims are intended to include such processes, machines, manufactures, compositions of matter, devices, methods, or steps within their scope.

Claims

1. An optical coupler (100), the optical coupler (100) comprising: A side-emitting electromagnetic radiation source (102) for emitting electromagnetic radiation at its side wall (104); An electromagnetic radiation detector (106) for detecting at least a part of the emitted electromagnetic radiation; A source carrier (116) on which the electromagnetic radiation source (102) is mounted; and A detector carrier (118) on which the electromagnetic radiation detector (106) is mounted, wherein the electromagnetic radiation detector (106) is configured to detect electromagnetic radiation at its upper main surface (108); wherein at least a part of at least one of the source carrier (116) and the detector carrier (118) is skewed such that the electromagnetic radiation source (102) and the electromagnetic radiation detector (106) are inclined relative to each other.

2. The optical coupler (100) according to claim 1, wherein, The electromagnetic radiation source (102) is a laser diode.

3. The optical coupler (100) according to claim 1 or 2, wherein, The electromagnetic radiation detector (106) is a photodiode.

4. The optical coupler (100) according to claim 1 or 2, wherein, The electromagnetic radiation source (102) and the electromagnetic radiation detector (106) are electrolytically decoupled from each other.

5. The optical coupler (100) according to claim 1 or 2, wherein, The electromagnetic radiation source (102) is configured to emit electromagnetic radiation only at its side wall (104).

6. The optical coupler (100) according to claim 1 or 2, wherein, The electromagnetic radiation detector (106) is configured to detect electromagnetic radiation only at its upper main surface (108).

7. The optical coupler (100) according to claim 1 or 2, comprising a control unit (110), the control unit (110) being coupled to the electromagnetic radiation detector (106) and configured to perform a control task based on the detected electromagnetic radiation.

8. The optical coupler (100) according to claim 1 or 2, comprising an optically transparent encapsulant (112), at least a part of the electromagnetic radiation source (102) and at least a part of the electromagnetic radiation detector (106) being embedded in the optically transparent encapsulant (112).

9. The optical coupler (100) according to claim 1 or 2, comprising a housing (130), the housing (130) surrounding at least a part of the electromagnetic radiation source (102) and at least a part of the electromagnetic radiation detector (106) and having a reflective inner surface (114), the reflective inner surface (114) being configured to reflect at least a part of the electromagnetic radiation emitted by the electromagnetic radiation source (102).

10. The optical coupler (100) according to claim 1 or 2, comprising at least one of the following features: wherein, The electromagnetic radiation source (102) is configured to emit red light; The optical coupler (100) is configured as a relay; wherein the electromagnetic radiation source (102) is configured to emit at least 60% of the intensity of the emitted electromagnetic radiation at its side wall (104) within an angular range (α) not greater than 45° about an axis perpendicular to the side wall (104); wherein the side-emitting electromagnetic radiation source (102) is configured to emit monochromatic electromagnetic radiation, and the electromagnetic radiation detector (106) is configured to detect only within a narrow wavelength band around the wavelength of the emitted monochromatic electromagnetic radiation; wherein the side-emitting electromagnetic radiation source (102) and the electromagnetic radiation detector (106) are arranged side by side.

11. The optical coupler (100) according to claim 1, comprising at least one of the following features: Wherein, The source carrier (116) and the detector carrier (118) are lead frames or separate parts of a common lead frame; wherein the source carrier (116) and the detector carrier (118) are arranged at the same vertical level (120); wherein the source carrier (116) is arranged at a higher vertical level (120) than the detector carrier (118) such that the side wall (104) of the electromagnetic radiation source (102) is arranged at a higher vertical level (120) than the side wall of the electromagnetic radiation detector (106).

12. The optical coupler (100) according to claim 1 or 2, comprising a deflector (122), the deflector (122) being arranged to deflect at least a portion of the emitted electromagnetic radiation onto the electromagnetic radiation detector (106).

13. The optical coupler (100) according to claim 12, comprising at least one of the following features: The deflector (122) is mounted on a detector carrier (118) on which the electromagnetic radiation detector (106) is mounted; The electromagnetic radiation detector (106) is arranged between the electromagnetic radiation source (102) and the deflector (122); The deflector (122) has a deflection surface (166), the deflection surface (166) being angled at a deflection angle (β) with respect to the incident electromagnetic radiation to be deflected onto the electromagnetic radiation detector (106); Wherein, The deflector (122) comprises or is made of a weldable material.

14. The optical coupler (100) according to claim 7, wherein, The control task is a switching task.

15. The optical coupler (100) according to claim 8, wherein, The optically transparent encapsulant (112) is a transparent gel.

16. The optical coupler (100) according to claim 9, wherein, The reflective inner surface (114) is configured to totally reflect the electromagnetic radiation emitted by the electromagnetic radiation source (102).

17. The optical coupler (100) according to claim 9, wherein, The reflective inner surface (114) is configured to reflect and direct at least a portion of the electromagnetic radiation onto the electromagnetic radiation detector (106).

18. The optical coupler (100) according to claim 10, wherein, The electromagnetic radiation source (102) is configured to emit only red light.

19. The optical coupler (100) according to claim 10, wherein, The relay is a solid-state relay.

20. The optical coupler (100) according to claim 10, wherein, The electromagnetic radiation source (102) is configured to emit at least 80% of the intensity of the emitted electromagnetic radiation within an angular range (α) of not more than 45° about an axis perpendicular to the side wall (104) at the side wall (104) thereof.

21. The optical coupler (100) according to claim 10, wherein, The electromagnetic radiation source (102) is configured to emit at least 60% of the intensity of the emitted electromagnetic radiation within an angular range (α) of not more than 30° about an axis perpendicular to the side wall (104) at the side wall (104) thereof.

22. The optical coupler (100) according to claim 10, wherein, The electromagnetic radiation source (102) is configured to emit at least 80% of the intensity of the emitted electromagnetic radiation within an angular range (α) of not more than 30° about an axis perpendicular to the side wall (104) at the side wall (104) thereof.

23. The optical coupler (100) according to claim 13, wherein, The deflection angle (β) is in the range between 30° and 60°.

24. The optical coupler (100) according to claim 13, wherein, The deflector (122) is welded to a detector carrier (118) on which the electromagnetic radiation detector (106) is mounted.

25. The optical coupler (100) according to claim 24, wherein, The detector carrier (118) is a lead frame.

26. A method of operating an optical coupler (100), wherein, The method includes: emitting electromagnetic radiation at a side wall (104) of a side-emitting electromagnetic radiation source (102); and detecting at least a portion of the emitted electromagnetic radiation by an electromagnetic radiation detector (106), wherein the optical coupler includes a source carrier (116) on which the electromagnetic radiation source (102) is mounted and a detector carrier (118) on which the electromagnetic radiation detector (106) is mounted; wherein the electromagnetic radiation detector (106) is configured to detect electromagnetic radiation at a main surface (108) thereof; wherein at least a portion of at least one of the source carrier (116) and the detector carrier (118) is skewed such that the electromagnetic radiation source (102) and the electromagnetic radiation detector (106) are inclined relative to each other.

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