DE102021210618A1 - OPTOELECTRONIC DEVICE - Google Patents

Abstract

An optoelectronic device is specified with a transmitter (1) which is set up to emit electromagnetic radiation (2) and to be operated with an input voltage (UI), - a receiver (3) which is set up to receiving electromagnetic radiation (2) and supplying an output voltage (UO), wherein- the transmitter (1) comprises an edge emitter (10), and- the receiver (3) comprises at least one photodiode (30).

Description

An optoelectronic device is specified.

One problem to be solved is to specify an optoelectronic device that can be made particularly compact.

In accordance with at least one embodiment, the optoelectronic device comprises a transmitter. The transmitter is set up to emit electromagnetic radiation. Furthermore, the transmitter is set up to be operated with an input voltage. The transmitter can, for example, be a component that generates electromagnetic radiation in the wavelength range between infrared radiation and UV radiation. In particular, the transmitter can be set up to generate electromagnetic radiation in the wavelength range from at least 350 nm to at most 1100 nm, in particular in the wavelength range from at least 800 nm to at most 950 nm, during operation.

In accordance with at least one embodiment of the optoelectronic device, the optoelectronic device comprises a receiver which is set up to receive the electromagnetic radiation and to supply an output voltage. The receiver is set up in particular to receive the electromagnetic radiation emitted by the transmitter during operation and to convert it at least partially into electrical energy. In particular, the receiver can be matched to the transmitter in such a way that the receiver has a particularly high level of absorption for the electromagnetic radiation generated by the transmitter.

According to at least one embodiment of the optoelectronic device, the transmitter comprises an edge emitter. In the present case, an edge emitter is understood to mean a radiation-emitting component which emits the electromagnetic radiation generated during operation transversely, in particular perpendicularly, to a side face or facet. The electromagnetic radiation is then emitted, for example, through the side surface or facet. In particular, the edge emitter can be a semiconductor component which has an epitaxially grown semiconductor body. The direction in which the electromagnetic radiation is then emitted during operation can in particular be oblique or perpendicular to a growth direction of the semiconductor body. For example, the semiconductor body can be based on semiconductor materials such as In(Ga)N, In(Ga)AlP, (Al)GaAs, (In)GaAs.

The edge emitter can be, for example, a light-emitting diode or a laser diode, in particular a superluminescent diode or an edge-emitting semiconductor laser. In this case, the transmitter can in particular also contain a single edge emitter which is operated with the input voltage. If the transmitter includes two or more edge emitters, which are connected in parallel or in series, for example, then the input voltage of the transmitter is calculated accordingly from the voltages with which the individual edge emitters are operated.

In accordance with at least one embodiment of the optoelectronic device, the optoelectronic device comprises a receiver which comprises at least one photodiode. The photodiode can comprise a semiconductor body with at least one detecting layer which is set up to absorb the electromagnetic radiation generated by the edge emitter during operation and to convert it into electrical energy. The at least one photodiode can be formed in the same material system as the edge emitter, for example. In particular, the receiver can comprise a large number of photodiodes which can be connected to one another in series or in parallel. The output voltage of the receiver is then calculated accordingly from the voltage that drops across the individual photodiodes.

According to at least one embodiment of the optoelectronic device, the optoelectronic device comprises a transmitter that is set up to emit electromagnetic radiation and to be operated with an input voltage, and a receiver that is set up to receive the electromagnetic radiation and to supply an output voltage , wherein the transmitter comprises an edge emitter and the receiver comprises at least one photodiode.

The optoelectronic device described here is based, inter alia, on the following considerations.

Many applications, such as in acoustics, in beam steering technologies such as MEMS, actuators, detectors such as avalanche photodiodes, single-photon avalanche diodes or photomultipliers, require high-voltage power supplies with relatively low power consumption. Such applications may require voltages in excess of 50V, 100V, 500V, 1000V, 2000V, 10000V and more while maintaining a small device footprint in terms of size, weight, cost and power consumption. These properties are particularly important for mobile Devices such as AR VR glasses, wearable earphones and automotive applications.

Another problem that needs to be solved for high-voltage generators with a small space requirement is the connection of low and high-voltage paths, which should be galvanically isolated in order to ensure the functional reliability and long-term stability of a device under changing environmental conditions such as temperature, humidity, dust.

The optoelectronic device described here can advantageously be used as an optical voltage converter. The optoelectronic device described here can thus form, for example, a transformer that does not require inductive elements, in particular without coils. On the one hand, this means that the installation space is particularly small compared to conventional transformers, and on the other hand, no strong magnetic fields are generated during the transformation. This also rules out any influence from external magnetic and/or electric fields. The optoelectronic device can thus be used in areas for which magnetic influence would be critical or which are provided with high external magnetic fields. At the same time, the optical power transmission in the optoelectronic device ensures galvanic isolation of the high-voltage side and the low-voltage side.

By eliminating the need to use switched elements, as is the case in boost or buck converters, for example, or even as would be necessary with an inductive transformer, the output voltage generated can be free of interference. This can be the case in particular when used in measuring systems and/or monitoring systems in the smallest of spaces, which react sensitively to disturbances in the supply voltage.

Another idea of the device described here is to combine semiconductor light emitters and photodiodes, i.e. photovoltaic cells, in order to achieve a conversion from low to high voltage. For this purpose, for example, one or more surface-emitting semiconductor lasers, light-emitting diodes or superluminescent diodes connected in parallel with one another emit light on the low-voltage path. The wavelength of the emitted light can be between 350 nm and 1100 nm depending on the semiconductor materials used, for example: In(Ga)N, In(Ga)AlP, (Al)GaAs, (In)GaAs. Typical input voltages are 1V, 3V, 5V, 8V, 10V or in between.

On the high-voltage side, which is galvanically isolated from the low-voltage side, an array of series-connected photodiodes operating in photovoltaic mode collects the emitted light. Depending on the material used, for example Si, InGaAs, GaAs, InGaN or perovskite, each individual photodiode generates a voltage of the order of 0.5-3 V and a current depending on the intensity of the incident light. By using a large number of photodiodes, all of which can be connected in series on a very small wafer scale, these individual voltages add up to a high total voltage that can exceed 10, 50, 100, 500, 1000, 10000 V.

Due to the high output power and high efficiency, above 60%, especially of edge-emitting semiconductor lasers, it is possible to use only a single or a small number of edge emitters to illuminate the photodiodes, which reduces the size and cost of the device on the transmitter side.

Also, due to the focused light cone of edge-emitting semiconductor lasers compared to other diode emitters, the distance and area of the receiver can be compressed to a small extent. The main limitations of miniaturizing the receiver are the material-dependent breakdown voltages within the receiver and the reduction in fill factor due to the circuitry.

Overall, with the present device, the wireless transmission of energy and/or the conversion of voltage is possible in a particularly compact component. The optoelectronic device is insensitive to external influences such as electromagnetic fields.

In accordance with at least one embodiment of the optoelectronic device, the input voltage is lower than the output voltage and the receiver comprises a multiplicity of photodiodes which are connected to one another in series. In this case, it is possible, for example, for the transmitter to also include a multiplicity of edge emitters, which are then connected up in parallel with one another, for example. In particular, the input voltage of the transmitter is smaller than the output voltage of the receiver. The device is therefore set up to convert a low input voltage into a high output voltage. For this purpose, the receiver can comprise a large number of photodiodes, for example at least 10 photodiodes, in particular at least 50 or at least 100 individual photodiodes. About the number of photodiodes that are connected in series with each other den, the output voltage can be easily adjusted.

According to at least one embodiment, the transmitter includes precisely one edge emitter. In this case, the transmitter comprises in particular precisely one edge-emitting semiconductor laser chip. Due to the high efficiency of edge emitters, in particular of edge-emitting semiconductor laser chips, it is possible for the transmitter to include exactly one edge emitter. As a result, the device can be made particularly compact.

In accordance with at least one embodiment, the optoelectronic device comprises an optical element which splits and/or bundles the electromagnetic radiation into a multiplicity of beams.

For example, the optoelectronic radiation is emitted in a single beam by the transmitter, for example by the edge emitter. The optical element can then be set up to split the optoelectronic radiation into a multiplicity of beams, it being possible for the multiplicity of beams to correspond to the number of photodiodes in the receiver. This ensures that each photodiode is irradiated with exactly one beam. In particular, it can also be made possible in this way for regions between the photodiodes on the receiver side not to be irradiated with the electromagnetic radiation. This makes the device particularly efficient.

Alternatively or additionally, the optical element can be provided to focus the electromagnetic radiation. In particular, the radiation is bundled in such a way that individual photodiodes of the receiver are irradiated and areas between the photodiodes are not irradiated. It is also possible for the optoelectronic device to comprise two or more such optical elements which are set up to split and/or bundle the electromagnetic radiation into a large number of beams.

In particular, the optical element can also form a second carrier for the receiver. For example, the photodiodes are applied to the second carrier. The second carrier can then in particular also be a growth substrate for the photodiodes of the receiver.

According to at least one embodiment of the optoelectronic device, each photodiode is uniquely assigned an optical element. This means that for each photodiode there is exactly one optical element that is intended to split and/or bundle the electromagnetic radiation.

In accordance with at least one embodiment of the optoelectronic device, the optoelectronic device comprises optics that deflect and/or direct the electromagnetic radiation from the transmitter to the receiver. For example, the optics can include radiation-refracting and/or radiation-reflecting elements that are set up to change the direction of the electromagnetic radiation, for example, in order to direct and/or guide it from the transmitter to the receiver. In this way, it is possible to mount the transmitter and receiver in an orientation that is optimized with regard to interconnection and/or heat dissipation, for example.

According to at least one embodiment of the device, at least one optical element is arranged between two adjacent photodiodes. This optical element can be provided for directing and/or conducting electromagnetic radiation onto the adjacent photodiodes. In particular, with such an optical element it can be ensured that electromagnetic radiation that impinges in a region between two adjacent photodiodes can still be used to generate energy by being deflected onto the photodiodes. In addition, the optical element or a carrier for the optical element can be designed to be electrically insulating. In this way, improved galvanic isolation of the receiver's photodiodes from one another is made possible.

In accordance with at least one embodiment of the optoelectronic device, the device comprises a carrier which has a cover surface, the transmitter and the receiver being arranged on the cover surface and a radiation entry side of the receiver being directed away from the cover surface.

With such a configuration of the device, it is possible to arrange the transmitter and receiver next to one another in a particularly compact manner on the top surface of a common carrier. In this way, the device can be designed with a particularly small footprint, for example it is also possible for the device to be designed to be surface mountable.

The carrier can in particular be a connection carrier on which the transmitter and the receiver are mechanically fastened and via which the transmitter and the receiver can be electrically contacted. It is possible that an interconnection of the photodiodes and possibly the edge emitter with each other via the carrier is done. The carrier may have vias that allow the device to be surface mountable. Furthermore, it is possible in this embodiment that the surface with which the receiver is in contact with the carrier is designed to be particularly large. This improves heat dissipation from the receiver to the carrier.

In accordance with at least one embodiment of the optoelectronic device, the carrier has a cover surface, the transmitter and the receiver being arranged on the cover surface and a radiation side of the receiver facing a radiation exit side of the transmitter. In this embodiment, the photodiodes of the receiver can therefore be irradiated directly by the transmitter with the electromagnetic radiation. There is therefore no need for optics that are set up to direct and/or guide the electromagnetic radiation from the transmitter to the receiver.

In accordance with at least one embodiment of the optoelectronic device, the device comprises a first carrier, on which the transmitter is arranged, and a second carrier, on which the receiver is arranged, the first carrier and the second carrier being arranged opposite one another.

This makes it possible, for example, to align the transmitter and receiver with one another in a simple manner in such a way that a radiation entry side of the receiver faces a radiation exit side of the transmitter.

The first carrier can in particular also be a growth substrate for the edge emitter of the transmitter. The second carrier can in particular also be a growth substrate for the photodiodes of the receiver.

In accordance with at least one embodiment of the optoelectronic device, the electromagnetic radiation expands from the edge emitter into a beam cone which has a larger opening angle in a vertical direction than in a horizontal direction, the vertical direction running transversely or perpendicularly to the top surface of the carrier. That is, the edge emitter of the transmitter is mounted in such a way that the fast axis of the electromagnetic radiation is perpendicular to the top surface of the carrier. In this way, when the receiver is aligned such that the radiation entry side of the receiver faces the radiation exit side of the transmitter, a particularly large area of the receiver can be illuminated directly.

According to at least one embodiment of the optoelectronic device, an electrically insulating filling material is arranged between the photodiodes. In this case, the electrically insulating filling material can be part of an optical element or serve as a carrier for an optical element which is arranged between the photodiodes in order to deflect and/or direct electromagnetic radiation onto them. In particular, the area or areas between the photodiodes of the receiver can be filled with the electrically insulating filling material. The filling material can border directly on the side of the photodiodes. In particular, the filling material makes it possible to prevent a high-voltage breakdown between the photodiodes. Furthermore, the filler material can act as a moisture barrier between the photodiodes and as protection for the wearer.

According to at least one embodiment of the optoelectronic device, the transmitter has a further radiation exit side, which is opposite the radiation exit side. In other words, the transmitter has two opposite radiation exit sides through which the electromagnetic radiation is emitted in each case. For example, the transmitter includes an edge emitter for this purpose, which emits the electromagnetic radiation from two opposite side surfaces or facets. Furthermore, it is possible for the transmitter to include two edge emitters which are mounted in such a way that the radiation exit sides of the individual edge emitters face away from one another.

In accordance with at least one embodiment of the optoelectronic device, a further receiver with a further radiation entry side is set up to receive electromagnetic radiation which exits at the further radiation exit side. This means that the further radiation exit side is also followed by a receiver which receives the electromagnetic radiation exiting at the further radiation exit side. The additional receiver can, for example, be structurally identical to the receiver. The additional receiver can therefore also include a large number of photodiodes. It is possible that the photodiodes of the receiver and the further receiver are connected to one another in series and the output voltages of the two receivers add up accordingly.

The optoelectronic device described here is explained in more detail below using exemplary embodiments and the associated figures.

Based on the schematic representations of 1 until 14 are examples of optoelectronic devices described here explained in more detail.

Elements that are the same, of the same type or have the same effect are provided with the same reference symbols in the figures. The figures and the relative sizes of the elements shown in the figures are not to be regarded as being to scale. Rather, individual elements can be shown in an exaggerated size for better representation and/or for better comprehensibility.

Based on the schematic sectional view of 1 a first exemplary embodiment of an optoelectronic device described here is explained in more detail.

The optoelectronic device comprises a transmitter 1 which emits electromagnetic radiation 2 during operation. For this purpose, the transmitter 1 comprises an edge emitter 10, which in the present case is an edge-emitting semiconductor laser. The edge emitter 10 emits the electromagnetic radiation 2 through a facet on its radiation exit side 11 . The transmitter 1 and thus the edge emitter 10 is attached to a first carrier 8 . The transmitter 1 is operated with the input voltage UI.

Opposite the transmitter 1, the optoelectronic device comprises a receiver 3, which receives the electromagnetic radiation and supplies an output voltage UO in the process. The receiver comprises a multiplicity of photodiodes 30 which receive the electromagnetic radiation on the radiation entry side 31 of the receiver 3 . The receiver 3 and thus the photodiodes 30 are attached to a second carrier 9 .

The optoelectronic device further comprises a carrier 7 which has a cover surface 71 . The transmitter 1 and the receiver 3 are arranged on the top surface 71 of the carrier 7 . The transmitter 1 and receiver 3 are mounted on the carrier 7 in such a way that the radiation entry side 31 of the receiver 3 faces the radiation exit side 11 of the transmitter 1 . The carrier 7 can be designed to be electrically insulating, for example, and is formed with a ceramic material for this purpose, for example.

The electromagnetic radiation from the transmitter 1, for example from the edge emitter 10, expands in a beam cone which has a larger opening angle in a vertical direction V than in a horizontal direction H. The vertical direction V runs perpendicular to the top surface 71 of the carrier 7 The opening angle of the beam cone is, for example, between at least 25 and at most 50 degrees in direction V. In the horizontal direction H, the opening angle is at least 5 and at most 20 degrees, for example.

The first carrier 8 for the transmitter 1 is designed so high that all the photodiodes 30 of the receiver 3 are illuminated.

The edge emitter 10 of the transmitter 1 and the photodiodes 30 of the receiver 3 can be formed in the same material system, for example. For example, they are each formed in one of the following material systems: (In)GaAs, (In)GaN, InGaAlP.

However, it is also possible for other materials, such as silicon, to be used on the receiver 3 side for the photodiodes. Photodiodes in this material system can be particularly inexpensive, but the efficiency of the system is greater for the same material systems on the transmitter 1 side and the receiver 3 side.

If the edge emitters 10 of the transmitter 1 and the photodiodes 30 of the receiver 3 are formed in the GaAs material system, the efficiency of the device is approximately 13%, assuming a filling factor of the receiver 3 with photodiodes 30 of 25%. This means that 13% of the electrical energy that is fed in at the transmitter end can be drawn off again at the receiver end. If one also takes into account the bandgap-to-Voc offset, ie the thermalization of the charge carriers, the result is an efficiency of 1eV/1.4eV=71% and a correspondingly reduced efficiency of the device of 9.3%. For example, the receiver 3 includes photodiodes 30 with an edge length of 10 μm and a spacing of 20 μm, at each of which a voltage of 1 V drops. With 18×30 photodiodes 30, this results in a size of the receiver 3 of approximately 0.36 mm×1.08 mm. For example, the transmitter 1 has a length of 1 mm and the distance between the transmitter 1 and the receiver 3 is 2.01 mm. This results in a minimum size of the device of 3.4×1.1×0.4 mm ² =1.5 mm ³ .

If the edge emitters 10 of the transmitter 1 and the photodiodes 30 of the receiver 3 are formed in the InGaAlP material system, the efficiency of the device is approximately 9%, assuming a fill factor of the receiver 3 with photodiodes 30 of 34%. This means that 9% of the electrical energy that is fed in at the transmitter end can be drawn off again at the receiver end. If one also takes into account the bandgap-to-Voc offset, i.e. the thermalization of the charge carriers, the result is an efficiency of 1.5eV/2.0eV=75% and a correspondingly reduced efficiency of the device of 6.75%. For example, the receiver 3 includes photodiodes 30 with an edge length of 14 μm and a spacing of 20 μm, at each of which a voltage of 1.5 V drops. With 14×45 photodiodes 30, this results in a size of the receiver 3 of approximately 0.30 mm×0.9 mm. For example, the transmitter 1 has a length of 1 mm and the distance between the transmitter 1 and the receiver 3 is 1.7 mm. This results in a minimum size of the device of 3.0×0.9×0.3 mm ² =0.8 mm ³ .

If the edge emitters 10 of the transmitter 1 and the photodiodes 30 of the receiver 3 are formed in the InGaN material system, the device has an efficiency of approximately 2%, assuming a fill factor of the receiver 3 with photodiodes 30 of 41%. This means that 2% of the electrical energy that is fed in at the transmitter end can be drawn off again at the receiver end. If one also takes into account the bandgap-to-Voc offset, ie the thermalization of the charge carriers, the result is an efficiency of 2.5eV/3.0eV=83% and a correspondingly reduced efficiency of the device of 1.66%. For example, the receiver 3 includes photodiodes 30 with an edge length of 20 μm and a spacing of 20 μm, at each of which a voltage of 2.5 V drops. With 12×36 photodiodes 30, this results in a size of the receiver 3 of approximately 0.24 mm×0.69 mm. For example, the transmitter 1 has a length of 1 mm and the distance between the transmitter 1 and the receiver 3 is 1.3 mm. This results in a minimum size of the device of 2.6×0.7×0.3 mm ² =0.6 mm ³ .

If the edge emitters 10 of the transmitter 1 are formed in the GaAs material system and the photodiodes 30 of the receiver 3 are formed in the Si material system, this results in an efficiency of the device of approximately 5.5% if a filling factor of the receiver 3 with photodiodes 30 is 25%. assumes This means that 5.5% of the electrical energy that is fed in at the transmitter end can be extracted again at the receiver end.

It is assumed here that the Si-based receiver comprises 3 photodiodes 30 with an edge length of 10 μm and a spacing of 20 μm, at each of which a voltage of 0.6 V drops. With 24×72 photodiodes 30, this results in a size of the receiver 3 of approximately 0.48 mm×1.44 mm. For example, the transmitter 1 has a length of 1 mm and the distance between the transmitter 1 and the receiver 3 is 2.69 mm. This results in a minimum size of the device of 4.1×1.5×0.5 mm ² =3.1 mm ³ . If one now further assumes that the transmitter 1 has an efficiency of 60%, the photodiodes 30 have an efficiency of 85%, the thermalization is 0.6eV/1.4eV=43% and the fill factor is 25%, this results a device efficiency of 5.5%.

Overall, the device described is characterized by a small and compact size. It is also advantageous that transmitter 1 and receiver 3 can be mounted on the same carrier 7 . The use of edge emitters 10 in transmitter 1 results in high efficiency. The component can be made particularly thin, with component heights of at most 0.4 mm being possible. In terms of device efficiency, the use of GaAs-based edge emitters and photodiodes is most advantageous. In view of the size of the device, the use of edge emitters 10 and photodiodes 30 based on InGaAlP is most advantageous without dropping the efficiency of the device too much.

The carrier 7 should be designed to be electrically insulating. This can be achieved, for example, by an electrically insulating layer below transmitter 1 and receiver 3. For example, a layer of AlGaAs with an aluminum content of 98% or SiN is suitable for this. The thickness of the layer should be 2.5 µm per 1000 V potential difference. For galvanic isolation between the transmitter 1 and the receiver 3, a distance of approximately 330 μm is also required for a potential difference of 1000 V if there is air between the two components.

In connection with the schematic sectional view of the 2 a further exemplary embodiment of an optoelectronic device described here is explained in more detail. In contrast to the embodiment of 1 an optical element 41 is arranged in the beam path of the electromagnetic radiation 2 and splits the electromagnetic radiation 2 into a plurality of beams 21 . The optical element is, for example, a diffractive optical element, which can consist of a photonic crystal array, for example.

The optical element generates beams 21, each beam 21 being able to be aimed at exactly one photodiode 30 of the receiver 3. In this way, the electromagnetic radiation 2 emitted by the transmitter 1 is distributed exclusively over the active areas of the receiver 3, ie the photodiodes 30, while the area between the photodiodes is not illuminated. This increases the device efficiency, which in the embodiment of 1 is reduced due to the fill factor of the photodiodes. For the examples given above, the changes in the efficiency or size of the device are as follows.

If the edge emitters 10 of the transmitter 1 and the photodiodes 30 of the receiver 3 are formed in the GaAs material system, the efficiency of the device is approximately 52%.

If the edge emitters 10 of the transmitter 1 and the photodiodes 30 of the receiver 3 are formed in the InGaAlP material system, the efficiency of the device is approximately 26%.

If the edge emitters 10 of the transmitter 1 and the photodiodes 30 of the receiver 3 are formed in the InGaN material system, the efficiency of the device is approximately 5%.

In this case, the optical element 41 can be in direct contact with the edge emitter 10 of the receiver 1 . It is also possible for the optical element 41 to be mechanically attached to the first carrier 8 as well, which improves the mechanical stability of the device.

This embodiment advantageously results in a very high efficiency of the device and a reduction in size. However, the adjustment effort associated with the attachment of the optical element 41 to the transmitter 1 is increased.

In connection with the 3 a further exemplary embodiment of an optoelectronic device described here is explained in more detail on the basis of a schematic sectional illustration.

In this exemplary embodiment, the transmitter 1 includes a further radiation exit side 12 which is opposite the radiation exit side 11 . Furthermore, the optoelectronic device comprises a further receiver 5 with a further radiation entry side 51 which receives the electromagnetic radiation 2 which exits at the further radiation exit side 12 . The further radiation entry side 51 is arranged opposite the radiation entry side 31 of the receiver.

The further diodes 50 of the further receiver 5 are arranged on the further second carrier 52 . The structure can, in particular, as in the 3 shown, be axisymmetric, the receiver 3 and the other receiver 5 can be identical.

An optical element 41, 42 can be arranged between the transmitter 1 and the receivers 3, 5, which splits the radiation 2 into a plurality of beams 21, so that each photodiode 30, 50 is illuminated by exactly one beam. With the in the 3 In the arrangement shown, for example, the number of photodiodes can be doubled, which means that the output voltage UO can be doubled if all the photodiodes 30, 50 are connected in series with one another.

The transmitter 1 can, for example, comprise an edge emitter 10, which has a low-reflecting mirror on each of the two radiation exit sides 11, 12. In the event that the optical elements 41, 42 in the embodiment of 3 are not used, the photodiodes 30, 50 are illuminated over a wide area. In this case, it is possible, for example, to use larger photodiodes 30 with the same output voltage UO, which improves the fill factor of the receivers 3, 5. Depending on whether the number of photodiodes 30, 50 with planar illumination equal to the number of photodiodes 30, such as in the embodiment of 1 , remains or the number of photodiodes 30, 50 is doubled and optical elements 41, 42 are used for beam splitting, correspondingly different sizes of the device result.

In connection with the schematic sectional view of the 4 a further exemplary embodiment of an optoelectronic device described here is explained in more detail. In the embodiment of 4 Optical elements 41 are arranged in the beam path of the electromagnetic radiation 2 and are set up to focus the electromagnetic radiation 2 onto the photodiodes 30 of the receiver 2 . For this purpose, the optical elements 41 are, for example, microlenses of a microlens array.

For this purpose, discrete microlenses are applied to each photodiode 30, for example. It is also possible that spin-on glass, for example, is applied to the photodiodes 30 in a wafer process and subsequently structured. Furthermore, in a wafer process, glass can first be spun on to flatten and insulate the photodiodes. Subsequently, discrete microlenses made of the same material can be applied. This results in particularly low reflection losses. Overall, this makes it possible for each photodiode 30 to be uniquely assigned an optical element 41 .

In this embodiment, it is advantageous that, compared to the planar illumination, as is the case, for example, in connection with the 1 is described, the entire light can be focused on the photodiodes 30 of the receiver 3 and this results in a fill factor of approximately 100%. Compared to optical elements 41, 42, as in connection with the 2 and 3 are described, there is less adjustment effort. For example, silicon dioxide or spin-on glass used to form the optical elements ments 41 can be used as insulators, which improves the breakdown stability on the receiver side 3. The disadvantage is that the production of the optical elements 41 can prove to be technically difficult, for example in a wafer process on the photodiodes 30 .

In connection with the schematic sectional view of the 5 a further exemplary embodiment of an optoelectronic device described here is explained in more detail. In this exemplary embodiment, optical elements 41 are arranged between adjacent photodiodes 30, each of which has a detecting layer 33, for example, which can be arranged between further semiconductor layers. The optical elements 41 are designed to be reflective and deflect electromagnetic radiation 2 onto the photodiodes 30 . In this case, the optical elements 41 can be formed, for example, as reflective layers which are formed with a metal such as gold or silver. The reflective layers are applied to an electrically insulating filling material 6 which is placed in the areas between the photodiodes 30 and can be in direct contact with the photodiodes 30 . In this way, electromagnetic radiation that would impinge on areas between the photodiodes 30 can be deflected onto them.

In this case, the optical elements 41 can be applied at the wafer level. For example, electrically insulating structures can be introduced between the photodiodes and shaped or spun on, onto which the optical elements 41 are then applied as a metal coating.

It is also possible to apply and attach a pre-structured frame to the array of photodiodes 30 . For example, the frame may comprise a plastic material such as polydimethylsiloxane printed with a metal.

It is also possible, for example, to apply a plastic material as filling material 6 through a stencil in the areas between the photodiodes 30 and then to apply the optical elements 41 to the filling material 6, likewise using the stencil. The plastic material can then be a silicone, for example.

The filling material 6 between the photodiodes 30 can electrically insulate them from one another. It also provides mechanical and chemical protection for the photodiodes 30, for example against moisture. Conductor tracks and contact points on the carrier 9 for the receiver 3 can also be mechanically and chemically protected as a result.

If the photodiodes 30 are arranged in a matrix-like manner in rows and columns and are connected in series along the columns, for example, then the distance between two columns is limited by the breakdown voltage. If the area between the photodiodes 30 of the receiver 3 is filled with air, there is a minimum distance of about 12 µm for photodiodes in the GaAs material system, a minimum distance of about 15 µm for photodiodes in the InGaAlP material system and a minimum distance of about 20 for photodiodes in the InGaN material system µm. If the area between the photodiodes 6 is filled with a filling material 6 that is formed with SiN or consists of this, there is a minimum spacing of approximately 90 nm for photodiodes in the GaAs material system, and a minimum spacing of approximately 113 nm for photodiodes in the InGaAlP material system Photodiodes in the InGaN material system have a minimum spacing of approximately 150 nm. With a dielectric filling material 6 between the photodiodes 30, they can therefore be arranged much closer together, which improves the filling factor.

In connection with the schematic sectional view of the 6 a further exemplary embodiment of an optoelectronic device described here is explained in more detail. In the embodiment of 6 includes the device in contrast to the embodiment of FIG 1 a receiver 3, in which the radiation entry side 31 is directed away from the top surface 71 of the carrier 7. In this way, the receiver 3 can be connected to the carrier 7 over a particularly large area, resulting in particularly good heat dissipation. The device also includes an optical system 4 which deflects the electromagnetic radiation 2 from the transmitter 1 to the receiver 3 . For example, the optics 4 include a prism as the optical element 41.

On the side of the optics 4 facing away from the photodiodes 30, an optical element 42 can optionally be arranged, which can be, for example, a metal mirror in particular.

The optical element 41, ie the prism of the optics 4, is shaped in such a way that the electromagnetic radiation 2 is distributed particularly evenly over all the photodiodes 30 of the receiver 3. The distance d between the transmitter 1 and the receiver 3, the height h of the receiver 3, i.e. the height of the outer surface of the photodiodes 30 facing away from the carrier 7 above the carrier 7, and the angle α of the optical element 41, i.e of the prism, be adjusted accordingly, to achieve uniform illumination of the photodiodes 30.

For example, the receiver includes 3 photodiodes 30 with an edge length of 10 μm and a spacing of 20 μm, at each of which a voltage of 1 V drops. With 32 × 32 photodiodes, this results in a size of the receiver of approximately 0.64 mm × 0.64 mm. The transmitter 1 has a length of 1 mm, for example, and the distance between the transmitter 1 and the receiver 3 is d=1 mm. The height h is 0.6 mm. This results in a minimum size of the device of 2.7×0.7×0.6 mm ² .

Advantageous results for the device 6 That all components are arranged on the same wafer plane and the device can be made particularly compact, especially for small distances d between the transmitter 1 and receiver 3. A disadvantage can arise that the illumination of areas between the photodiodes 30 reduces efficiency .

In connection with the schematic sectional view of the 7 a further exemplary embodiment of the device described here is explained in more detail. In this embodiment, an optical element 43 , which is a diffractive optical element, for example, is introduced between the transmitter 1 and the receiver 3 . The optical element 43 splits the electromagnetic radiation 2 into a multitude of beams 21, which are diverted by the optics 4 in such a way that each photodiode 30 is illuminated with exactly one beam and the areas between the photodiodes 30 remain free of illumination. This increases the device efficiency since the filling factor of the photodiodes 30 in the receiver 3 is no longer relevant. The disadvantage is that the optics 4, the photodiodes 30 and the optical element 43 have to be adjusted very precisely. In this case, the optical element 43 can be in direct contact with the edge emitter 10 of the transmitter 1 . Furthermore, there can be direct contact between the first carrier 8 and the optical element 43 for improved mechanical stability.

In connection with the schematic sectional view of the 8th a further exemplary embodiment of a device described here is explained in more detail. In contrast to the embodiment of 7 the optical element 43 in this embodiment is designed as a structuring of the optical element 41 of the optics 4 . This means that instead of a separate optical element 43, a diffractive optical element, for example, is integrated into the optical element 41 as the optical element. This can be realized, for example, by nanostructuring, which can be done, for example, by lithography or nanoprinting. In this way, a photonic crystal array, for example, is formed on the light entrance side of the optical element 41 .

This advantageously results in a reduced adjustment effort, since only the prism has to be aligned with the arrangement of the photodiodes 30 of the receiver 3 . Furthermore, reduced costs can result since a separate optical element 43 does not have to be manufactured. The disadvantage is that the optics 4 have to be processed from different sides, in particular if an optical element 42 is attached to the side of the optics 4 facing away from the photodiodes 30 .

In connection with the schematic sectional view of the 9 a further exemplary embodiment of a device described here is explained in more detail. In contrast to the embodiment of 8th the optical element 43, which is provided for dividing the radiation 2 into a plurality of beams 21, is integrated into the surface of the reflecting side of the optics 4. In the event that an optical element 42 is present in the form of a mirror, this simplifies the production of the optics 4 since both the optical element 43 and the optical element 42 lie directly one above the other.

In connection with the schematic sectional view of the 10 a further exemplary embodiment of a device described here is explained in more detail. In this exemplary embodiment, there is no optical element which causes the electromagnetic radiation 2 to be divided into a plurality of beams 21, but rather optical elements 43, which are designed as microlenses, are integrated into the optics 4 or applied to the optics 4, for example glued. In this case, the optical elements 43 are set up to focus the electromagnetic radiation 2 onto the photodiodes 30 .

In connection with the schematic sectional view of the 11 an exemplary embodiment is shown in which such optical elements 43, which are designed as microlenses, are attached to the radiation entry side of the optics 4.

In connection with the schematic sectional view of the 12 an exemplary embodiment is described in which the optics 4 are formed by the second carrier 9 for the photodiodes 30 . In particular, the second carrier 9 can also be a growth substrate for the photodiodes 30 here. In the embodiment of 12 is an optical element 43, which is a diffractive optical element that is set up to split the electromagnetic radiation 2 into a plurality of beams 21, arranged between the transmitter 1 and the receiver 3.

• - Kantenemitter 10 basierend auf GaAs mit einem GaAs-Aufwachssubstrat, oder Saphir oder Glasträger als zweiten Träger 9 mit InGaAs-basierten Fotodioden 30,
• - Kantenemitter 10 basierend auf InGaN mit einem GaN-Aufwachssubstrat oder einem Saphir-Aufwachssubstrat als zweiten Träger 9 mit InGaN-basierten Fotodioden 30,
• - Kantenemitter 10 basierend auf InGaAlP mit einem zweiten Träger 3 aus Saphir oder Glas mit InGaAlP-basierten Fotodioden 30.

In this exemplary embodiment, the photodiodes 30 face the carrier 7 and are glued to it, for example. In addition, electrically insulating materials can be arranged between the photodiodes 30 and between the photodiodes 30 and the carrier 7 . For this purpose, for example, a filling material 6 described here can be used. Exemplary material combinations for forming the edge emitter 10 and the second carrier 9 are, for example:

• - Edge emitter 10 based on GaAs with a GaAs growth substrate, or sapphire or glass substrate as the second substrate 9 with InGaAs-based photodiodes 30,
• - Edge emitter 10 based on InGaN with a GaN growth substrate or a sapphire growth substrate as the second carrier 9 with InGaN-based photodiodes 30,
• - Edge emitter 10 based on InGaAlP with a second carrier 3 made of sapphire or glass with InGaAlP-based photodiodes 30.

With an electrically conductive second carrier 9, which consists of GaAs, for example, or is formed with it, electrical insulation between the photodiodes 30 can be realized, for example, by an oxidation layer made of AlGaAs with a high aluminum content of, for example, 98% or more. The oxidation layer can be epitaxially integrated below the photodiodes 30 . This advantageously results in an optical element 4 that is monolithically integrated into the second carrier 2 and thus in a lower complexity in comparison with discrete components. Furthermore, due to the smaller number of reflective interfaces, there is increased efficiency. A disadvantage can result in light scattering of the second carrier 2 due to defects. The interconnection of the photodiodes 30 on the second carrier 2 and the insulation of the photodiodes 30 can also be more complex.

In connection with the schematic sectional view of the 13 a further exemplary embodiment of an optoelectronic device described here is explained in more detail. Analogous to the embodiment of 9 In this exemplary embodiment, an optical element 43, which is set up to split the electromagnetic radiation 2 into a multiplicity of beams 21, is integrated into the optical element 42, which is a mirror.

In connection with the 14 a further exemplary embodiment of an optoelectronic device described here is explained in more detail. In this exemplary embodiment, the optical element 43, which is provided for dividing the electromagnetic radiation 2 into a plurality of beams 21, is analogous to the exemplary embodiment in FIG 8th integrated into the radiation entrance side of the optics 4, which is formed by the second carrier 9.

The invention is not limited to these by the description based on the exemplary embodiments. Rather, the invention encompasses every new feature and every combination of features, which in particular includes every combination of features in the patent claims, even if this feature or this combination itself is not explicitly stated in the patent claims or exemplary embodiments.

Reference List

1

Channel

2

electromagnetic radiation

3

Recipient

4

optics

5

additional recipient

6

filling material

7

carrier

8th

first carrier

9

second carrier

10

edge emitter

11

radiation exit side

12

further radiation exit side

21

rays

30

photodiode

31

radiation entry side

33

detecting layer

41

optical element

42

optical element

43

optical element

50

another photodiode

51

further radiation entry side

52

another second carrier

71

top surface

UI

input voltage

UO

output voltage

V

vertical direction

H

horizontal direction

a

prism angle

H

Height

i.e

Distance

Claims (16)

Optoelectronic device with - a transmitter (1) which is set up to emit electromagnetic radiation (2) and to be operated with an input voltage (UI), - A receiver (3) which is set up to receive the electromagnetic radiation (2) and to supply an output voltage (UO), wherein - the transmitter (1) comprises an edge emitter (10), and - The receiver (3) comprises at least one photodiode (30). Optoelectronic device according to the preceding claim, in which the input voltage (UI) is lower than the output voltage (UO) and the receiver (3) comprises a multiplicity of photodiodes (30) which are connected to one another in series. Optoelectronic device according to one of the preceding claims, in which the transmitter (1) comprises exactly one edge emitter (10). Optoelectronic device according to one of the preceding claims, in which an optical element (41, 42, 43) divides and/or bundles the electromagnetic radiation (2) into a large number of beams (21). Optoelectronic device according to the preceding claim, in which each photodiode (30) is uniquely associated with an optical element (41, 42). Optoelectronic device according to one of the preceding claims, in which an optical system (4) directs and/or guides the electromagnetic radiation (2) from the transmitter (1) to the receiver (3). Optoelectronic device according to the preceding claim, in which the optics (4) form a second support (9) on which the receiver (3) is arranged. Optoelectronic device according to the preceding claim, in which the second support (9) is a growth substrate for the photodiodes (30) of the receiver (3). Optoelectronic device according to one of the preceding claims, in which at least one optical element (41, 42) is arranged between two adjacent photodiodes (30). Optoelectronic device according to one of the preceding claims with a carrier (7) which has a cover surface (71), the transmitter (1) and the receiver (3) being arranged on the cover surface (71) and a radiation entry side (31) of the receiver is directed away from the top surface (71). Optoelectronic device according to any one of Claims 1 until 9 with a carrier (7) which has a cover surface (71), the transmitter (1) and the receiver (3) being arranged on the cover surface (71) and a radiation entry side (31) of the receiver (3) being a radiation exit side (11 ) of the transmitter (1) is facing. Optoelectronic device according to one of the preceding claims, having a first carrier (8) on which the transmitter (1) is arranged and a second carrier (9) on which the receiver (3) is arranged, the first carrier (8) and the second carrier (9) are arranged opposite to each other. Optoelectronic device according to any one of Claims 10 until 12 , in which the electromagnetic radiation (2) from the transmitter (1) expands in a beam cone which has a larger opening angle in a vertical direction (V) than in a horizontal direction (H), the vertical direction (V) being transverse or perpendicular to the top surface (71) of the carrier (7). Optoelectronic device according to one of the preceding claims, having an electrically insulating filling material (6) between two adjacent photodiodes (30). Optoelectronic device according to one of the preceding claims, in which the transmitter (1) has a further radiation exit side (12) which is opposite the radiation exit side (11). Optoelectronic device according to the preceding claim, in which a further receiver (5) with a further radiation entry side (51) is set up to receive electromagnetic radiation (2) which exits on the further radiation exit side (12).

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