An optoelectronic component is specified.
The document WO 2004/077558 A1 describes an optoelectronic component.
One object to be achieved is to specify an optoelectronic component which is particularly compact.
In accordance with at least one embodiment of the optoelectronic component, the optoelectronic component comprises a circuit board. The circuit board comprises, for example, a base body formed with an electrically insulating material. Conductor tracks and electrical connection locations serving for making electrical contact with components of the optoelectronic component which are applied to the circuit board are structured onto and/or into the base body.
The circuit board comprises, for example, a base body formed with a plastics material. In this case, the base body can consist of the plastics material. By way of example, the circuit board is a printed circuit board (PCB).
The circuit board comprises a top side, which is formed, for example, by a first main area of the circuit board. Furthermore, the circuit board comprises an underside facing away from the top side. At its top side, the circuit board has a chip connection region. The chip connection region is, for example, a metalized region of the circuit board to which, for example, an optoelectronic semiconductor chip can be fixed and electrically conductively connected. In this case, the circuit board can also have two or more chip connection regions formed in identical design at its top side.
In accordance with at least one embodiment of the optoelectronic component, the optoelectronic component comprises an optoelectronic semiconductor chip, which is fixed to the chip connection region. The optoelectronic semiconductor chip can, for example, be soldered to the chip connection region or adhesively bonded thereon. The optoelectronic semiconductor chip is a radiation-receiving or a radiation-emitting optoelectronic semiconductor chip. By way of example, the optoelectronic semiconductor chip is a light emitting diode chip suitable, during operation, for generating electromagnetic radiation from the infrared range, the spectral range for visible light and/or the spectral range of UV radiation. The component can also comprise two or more optoelectronic semiconductor chips, wherein each optoelectronic semiconductor chip is fixed to a chip connection region.
Preferably, the optoelectronic semiconductor chip is a surface emitter. That is to say that the optoelectronic semiconductor chip emits the emitted electromagnetic radiation for the most part or completely through a main area, for example at the top side of the optoelectronic semiconductor chip. Hardly any or no electromagnetic radiation at all is then emitted through the side areas of the optoelectronic semiconductor chip. For this purpose, the optoelectronic semiconductor chip is preferably embodied as a thin-film light emitting diode chip.
A thin-film light emitting diode chip is preferably distinguished by at least one of the following characteristic features:
A thin-film light emitting diode chip is to a good approximation a Lambertian surface emitter and is therefore well suited, for example, to application in a headlight, for instance a motor vehicle headlight.
In accordance with at least one embodiment of the optoelectronic component, the component comprises a housing body, which is fixed to the circuit board at the top side of the circuit board. By way of example, the housing body can be fixed to the circuit board at the top side thereof by means of an adhesive. Furthermore, it is possible for the housing body to be fixed to the circuit board in a manner free of connecting means. For this purpose, the housing body can be integrally molded onto the top side of the circuit board by means of an injection molding method or a transfer molding method, for example. A mechanical connection between housing body and circuit board can be effected, for example, during the curing of the material of the housing body.
The housing body has a reflector region. The reflector region is provided for reflecting electromagnetic radiation generated by the optoelectronic semiconductor chip during operation or electromagnetic radiation to be detected by the optoelectronic semiconductor chip during operation.
In accordance with at least one embodiment of the optoelectronic component, the reflector region comprises an opening in the housing body, the optoelectronic semiconductor chip being arranged in said opening. In this case, the opening preferably extends from the top side of the housing body facing away from the circuit board to the underside of the housing body facing the circuit board. That means that the circuit board with the chip connection region is exposed inside the opening. In this way, the housing body surrounds the optoelectronic semiconductor chip at least in places in the region of the opening. The side areas of the housing body in the opening which face the optoelectronic semiconductor chip form radiation-reflecting areas of the reflector region—that is to say the reflector area—and can be coated suitably for this purpose, for example. If the component has two or more optoelectronic semiconductor chips, then two or more optoelectronic semiconductor chips can be arranged in an opening. Furthermore, it is then also possible for the reflector region to comprise two or more openings and for exactly one optoelectronic semiconductor chip to be arranged in each opening.
In accordance with at least one embodiment of the optoelectronic component, the optoelectronic semiconductor chip is embedded into a potting, which appears white, black or colored, wherein that surface of the optoelectronic semiconductor chip which faces away from the chip connection region is free of the potting at least in places. In particular, the potting can have the color of the outer area of the housing body.
The potting can be embodied as radiation-opaque. The potting is embodied as reflective, for example. For this purpose, the potting can comprise, for example, a matrix material composed of silicone and/or epoxide filled with reflective particles, for example composed of titanium oxide.
Furthermore, it is possible for the particles to consist of ZrO2 or at least to contain ZrO2. If the semiconductor chip emits blue or ultraviolet light, ZrO2 has particularly low absorption properties in such a wavelength range. In other words, a high proportion of electromagnetic radiation is reflected by the potting in this case.
Overall, it is possible for the radiation-reflecting particles to consist at least of one of the materials TiO2, BaSO4, ZnO, AlxOy, ZrO2 or to contain one of the materials mentioned. The potting then appears as white, for example.
Furthermore, it is possible for the potting to be filled with radiation-absorbing particles, for example composed of carbon black, such that the potting appears black.
The optoelectronic semiconductor chip is preferably a surface emitter embodied, for example, as a thin-film light emitting diode chip. That is to say that the optoelectronic semiconductor chip is then, in particular, not a volume emitter. That is to say that hardly any electromagnetic radiation emerges through the side areas of the semiconductor chip in this case.
In accordance with at least one embodiment of the optoelectronic component, the housing body is formed with a plastics material. The plastics material is preferably a plastics material which is particularly stable thermally and which is preferably melt-processable. By way of example, for this purpose the housing body is formed with a polyphenyl sulfide (PPS). The base body of the circuit board can then be formed with the same plastics material or with a plastics material having a similar coefficient of thermal expansion.
In accordance with at least one embodiment of the optoelectronic component, the housing body is metalized in the reflector region at least in places. That is to say that parts of the housing body, for example in the opening in the housing body, are covered by a metal layer at least in places. By way of example, a reflector area of the reflector region can be formed by the metalized regions of the housing body. The housing body is then metalized, for example, only in the opening of the reflector region; other parts of the housing body are free of the metalization. However, it is also possible for all exposed outer areas of the housing body to be metalized. Such an embodiment of the optoelectronic component can be produced particularly simply.
The metalization of the housing body can be applied to the plastics material of the housing body by means of thermal evaporation, for example. The metal which is applied to the housing body in this case is selected with regard to the electromagnetic radiation to be detected or emitted by the optoelectronic semiconductor chip during operation. By way of example, gold is suitable for infrared radiation having wavelengths of 800 nm or more. A metalization comprising silver or aluminum is suitable, in particular for the visible range. The metal of the metalization is preferably applied directly to the housing body. When using metals which tend toward corrosion and diffusion, a passivation layer is applied to the metalization at its side facing away from the housing body, said passivation layer being embodied as radiation-transmissive and preferably transparent to the radiation to be reflected. The passivation layer can be formed, for example, with a silicon oxide and/or a silicon nitride.
In accordance with at least one embodiment of the optoelectronic component, the component comprises a circuit board, which has a top side having a chip connection region, an optoelectronic semiconductor chip, which is fixed to the chip connection region, a housing body, which is fixed to the circuit board at the top side of the circuit board and has a reflector region, wherein the reflector region comprises an opening in the housing body, the optoelectronic semiconductor chip being arranged in said opening, and the housing body is formed with a plastics material which is metalized at least in places in the reflector region.
In this case, the optoelectronic component described here is based on the following concepts, inter alia:
In accordance with at least one embodiment of the optoelectronic component, the circuit board has at its top side a wire connection region, which is spaced apart from the chip connection region. That is to say that wire connection region and chip connection region are both arranged at the top side of the circuit board, for example are electrically insulated from one another by means of the base body of the circuit board and are arranged at a distance from another at the top side of the circuit board. The housing body furthermore has a wire region, which comprises an opening in the housing body. In this case, the wire region is spaced apart from the reflector region. That is to say, for example, that reflector region and wire region do not comprise the same opening in the housing body, rather that at least two openings are formed in the housing body and completely penetrate through the housing body, wherein the first opening is assigned to the reflector region and the second opening is assigned to the wire region. The wire connection region of the circuit board is then arranged in the second opening, that is to say in the wire region. The opening therefore forms a perforation in the housing body at which at least the wire connection region at the top side of the circuit board is exposed.
In accordance with at least one embodiment of the optoelectronic component, the optoelectronic component comprises a connection wire, which is fixed to the optoelectronic semiconductor chip and to the wire connection region. By means of the connection wire, electrical contact is made with the optoelectronic semiconductor chip on the n-side, for example. In this case, the connection wire is led through a cutout in the housing body, said cutout connecting the reflector region and the wire region to one another. By way of example, the cutout is embodied as a tunnel or trench in the housing material which extends from the reflector region to the wire region. At a bottom area of the cutout, the circuit board can in this case be exposed in places. In this case, the cutout is, for example a perforation in the housing body. However, it is also possible for the housing body not to be completely removed in the region of the cutout, such that the bottom area of the cutout is formed by material of the housing body. In any case, the connection wire is led through the cutout between reflector region and wire region in such a way that the connection wire does not project beyond a top side of the housing body facing away from the circuit board.
In accordance with at least one embodiment of the optoelectronic component, the housing body completely covers the circuit board apart from the reflector region and, if present, the wire region and the cutout, at the top side of the circuit board. That is to say that the top side of the circuit board is covered by the housing body and not accessible and/or not visible externally apart from the regions mentioned.
In accordance with at least one embodiment of the housing body, at least one side area of the housing body terminates at least in places flush with at least one side area of the circuit board. By way of example, it is possible for all side areas of housing body and circuit board to terminate flush with one another.
In accordance with at least one embodiment, the base area of the housing body has the same form as the base area of the circuit board, and/or the base area of the housing body has the same size as the base area of the circuit board. If the circuit board is embodied as rectangular or square, for example, then the housing body is a parallelepiped. The side areas of circuit board and housing body can then terminate flush with one another. Overall, the optoelectronic component then has the form of a parallelepiped in which the underside is formed by the circuit board. The at least one opening in the reflector region is situated at the top side of the parallelepiped facing away from the underside.
In accordance with at least one embodiment of the optoelectronic component, the reflector region comprises a reflector opening in proximity to the chip and a reflector opening remote from the chip. In this case, by way of example, the opening assigned to the reflector region tapers from the reflector opening remote from the chip to the reflector opening in proximity to the chip. That is to say, in particular, that the reflector opening remote from the chip has a larger area content than the reflector opening in proximity to the chip. At least one reflector area of the reflector region connects the reflector opening in proximity to the chip and the reflector opening remote from the chip to one another. The reflector area is formed, for example, by the metalized housing body of the optoelectronic component within the opening. That is to say that the reflector area is formed by a part of the housing body which is metalized at least in places. In this case, it is possible, in particular, for the housing body to be metalized only in the region of the reflector area, such that particularly little metal is required for forming the metalization.
In accordance with at least one embodiment of the optoelectronic component, the reflector opening in proximity to the chip has an area content which is at most four times the magnitude of the area content of the main area of the optoelectronic semiconductor chip which faces away from the circuit board. By way of example, the main area of the semiconductor chip is the top area thereof. A radiation emission in the case of a radiation-emitting optoelectronic semiconductor chip can then be effected, for example, for the most part through said main area. Such a particularly small reflector opening in proximity to the chip can be achieved by virtue of the fact that the wire connection region of the optoelectronic component is arranged in a manner spaced apart from the chip connection region and the wire region of the housing body can thus be arranged in a manner spaced apart from the reflector opening. In this way, the reflector opening can be chosen to be particularly small and has to be dimensioned only with regard to its optical properties.
In accordance with at least one embodiment of the optoelectronic component, the circuit board has an underside facing away from the top side, wherein component connection regions are formed at the underside of the circuit board. The optoelectronic component is surface-mountable by means of said component connection regions.
In accordance with at least one embodiment of the optoelectronic component, the optoelectronic component has a thickness of at most 1 mm, wherein the circuit board has a thickness of at most 0.35 mm and the housing body has a thickness of at most 0.65 mm. Such a small thickness of the optoelectronic component is made possible, in particular, by the use of a circuit board having a base body composed of plastic and a housing body which can be produced by means of an injection molding method or a transfer molding method. The use of a circuit board having a base body composed of plastic makes possible a particularly thin circuit board. The production methods mentioned allow the housing body and in particular the reflector region to be produced in a manner exhibiting particularly accurate register.
The optoelectronic component described here is explained in greater detail below on the basis of exemplary embodiments and the associated figures.
Elements that are identical, of identical type or act identically are provided with the same reference signs in the figures. The figures and the size relationships of the elements illustrated in the figures among one another should not be regarded as to scale. Rather, individual elements may be illustrated with an exaggerated size in order to enable better illustration and/or in order to afford a better understanding.
Circuit board 1 and housing body 3 have a rectangular base area of identical form and size. Overall, the optoelectronic component has a parallelepipedal form, wherein the underside of the parallelepiped is formed by the circuit board 1.
Two openings 31, 33 and a cutout 34 toward the circuit board 1 are formed at the top side 3a of the housing body 3.
The reflector region 30 comprises the first opening 31. The first opening 31 extends from the top side 3a of the housing body 3 to the top side 1a of the circuit board 1, such that the top side 1a of the circuit board 1 is exposed in places in the region of the opening 31. The circuit board 1 comprises the chip connection region 10 there. An optoelectronic semiconductor chip 2, for example a light emitting diode chip, is fixed and electrically connected to the chip connection region 10.
The reflector area 30c extends around the optoelectronic semiconductor chip 2. The reflector area is formed, for example by the housing body 3 in the region of the opening 31, said housing body being coated there at least with a metal layer 5 (in this respect, cf. for example the sectional illustration in
A ring 30d can be adjacent to the reflector area 30c, which runs obliquely with respect to the top side 1a of the circuit board 1, which ring runs perpendicularly or substantially perpendicularly to the circuit board 1 at its top side 1a (in this respect, cf. the schematic, perspective sectional illustration in
The housing body 3 has a second opening 33, the wire region 32 comprising said second opening. The top side 1a of the circuit board 1 with the wire connection region 12 is exposed in the opening 33.
A connection wire 4 for making electrical contact with the optoelectronic semiconductor chip 2 is led from the optoelectronic semiconductor chip 2 to the wire connection region 12 and is fixed to the optoelectronic semiconductor chip 2 and to the wire connection region 12.
In this case, the connection wire 4 is led through the cutout 34, in which the reflector area 30c is perforated in places. The top side 1a of the circuit board 1 can be exposed at the bottom area 34a (cf. the schematic plan view in
The opening 31, the reflector region 30 comprising this opening, can be filled with a radiation-transmissive potting material which reaches as far as the top side 3a of the base body 3 or projects beyond the latter. The opening 33, the wire region 32 comprising this opening, and the cutout 34 can be covered with a potting material having, for example, the same color as the base body 3 at its top side 3a, such that the wire region 32 cannot be discerned externally. Furthermore, it is possible for the potting to be embodied as black and thus to be suitable for absorbing stray light, for example.
The schematic sectional illustration in
In conjunction with the plan view of the underside 1b of the circuit board 1 in
The potting 35 can be embodied as radiation-opaque. For example, the potting is embodied as reflective. For this purpose, the potting 35 can comprise, for example, a matrix material composed of silicone and/or epoxide filled with reflective particles, for example composed of titanium oxide. The potting then appears as white.
Furthermore, it is possible for the particles to consist of ZrO2 or at least to contain ZrO2. If the semiconductor chip 2 emits blue or ultraviolet light, ZrO2 has particularly low absorption properties in such a wavelength range. In other words, a high fraction of electromagnetic radiation is reflected by the potting in this case.
Overall, it is possible for the radiation-reflecting particles to consist at least of one of the materials TiO2, BaSO4, ZnO, AlxOy, ZrO2 or to contain one of the materials mentioned.
Furthermore, it is possible for the potting 35 to be filled with radiation-absorbing particles, for example composed of carbon black, such that the potting 35 appears black. The optoelectronic semiconductor chip 2 is preferably a surface emitter embodied, for example, as a thin-film light emitting diode chip. That is to say that the optoelectronic semiconductor chip 2 is then, in particular, not a volume emitter.
The invention is not restricted to the exemplary embodiments by the description on the basis of said exemplary embodiments. Rather, the invention encompasses any novel feature and also any combination of features, which in particular includes any combination of features in the patent claims, even if this feature or this combination itself is not explicitly specified in the patent claims or exemplary embodiments.
This patent application claims the priority of German patent application 102010023955.0, the disclosure content of which is hereby incorporated by reference.
Number | Date | Country | Kind |
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10 2010 023 955.0 | Jun 2010 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2011/058489 | 5/24/2011 | WO | 00 | 1/28/2013 |