Patent Application
20170288108
Various embodiments relate to an optoelectronic device and to a method for producing an optoelectronic device.
Optoelectronic devices including a light-emitting diode are known as such. In principle, here there is a need for a flexible package concept for improving a device design with regard to interconnectability (complex multi-chip modules, vertical soldering pad structures), device geometry and integration of optics.
The problem addressed by the present disclosure can therefore be considered that of providing an optoelectronic device which enables an improved and flexible interconnectability and an improved integration of optics.
The problem addressed by the present disclosure can also be considered that of specifying a corresponding method for producing an optoelectronic device.
These problems are solved by the respective subject matter of the independent claims. Advantageous configurations of the present disclosure are the subject matter of respectively dependent subclaims.
According to one aspect, an optoelectronic device is provided, including:
In accordance with a further aspect, a method for producing an optoelectronic device is provided, including the following steps:
The present disclosure thus includes, in particular, the concept of advantageously combining with one another firstly printed circuit board technology and secondly molding that is known from QFN technology. In this case, “QFN” stands for “quad flat no leads package”. As a result, the advantages afforded by both technologies can advantageously be combined with one another. The optoelectronic device thus has advantages of the two technologies. This advantageously makes it possible, for example, on account of providing the electrical printed circuit board, to bring about a flexible electrical contacting for the light-emitting diode. That is to say, for example, that a high flexibility with regard to an interconnectability of the light-emitting diode is provided. Here the printed circuit board affords the technical advantage, in particular, that a multiplicity of electrical circuit layouts are possible for optimally electrically contacting the light-emitting diode. Moreover, a number of potentials for the diodes is furthermore advantageously not limited. In particular, this advantageously makes it possible to integrate further electronic devices, for example a protective diode or freewheeling diode and also a temperature sensor, in particular an NTC (negative temperature coefficient thermistor) sensor, or else other sensor system or analysis system components on the printed circuit board.
Molding in the sense of the present disclosure denotes transfer molding, in particular film assisted transfer molding. That is to say that molding is based on a transfer molding method, in particular a film assisted transfer molding method. This is in contrast to a traditional potting process, in which a homogeneous and planar surface cannot arise. In the meantime, in the case of transfer molding, in particular in the case of film assisted transfer molding, the electronic devices (diode, chips, NTC sensor, further electronic devices) and further components can be completely embedded. In this case, a defined and smooth surface advantageously arises. If sealing is effected for example by mans of the film on the chip surface, then the encapsulating material (the potting compound) is also at the same height level. This is provided in this way according to one embodiment.
The fact that the light-emitting diode is at least partly enclosed by transfer molding or enclosed by molding by the potting compound, which can also be referred to as molding compound, for example, affords the technical advantage, in particular, that good protection of the light-emitting diode against external influences is provided. In particular, the areas that are potted by the potting compound need not have an anticorrosion layer, since said areas are encapsulated by means of the potting compound. This analogously also applies to a soldering resist, which thus no longer need be applied on the areas that are potted by transfer molding or enclosed by molding by means of the potting compound.
The potting compound also advantageously makes it possible to conceal specific structures or components on the printed circuit board, that is to say make them virtually invisible. The components that are enclosed by molding or embedded are concealed from a user who looks at the device from outside. This is expedient particularly with regard to a visually attractive design. In particular, a homogeneous visual impression of the device is brought about as a result. In particular, a homogeneous color impression of the device is brought about. The color corresponding to the color impression results, in particular, from the color of the potting compound. That is to say therefore, in particular, that a specific color impression, for example a white color impression, for a user can be generated by means of a correspondingly chosen potting compound.
Furthermore, a flexible device geometry, for example round or angular, is made possible. This is the case, in particular, because a printed circuit board can be manufactured, for example cut, in a tailored shape as desired. That is to say, in particular, that the printed circuit board can have flexible shapes, for example round or angular. During molding, the potting compound then adapts to this shape of the printed circuit board given appropriate selection of the molding tool or molding insert required for this purpose.
Furthermore, the potting compound makes it possible, in a simple manner, to produce further structures, for example a reflector structure or a cavity, which are formed from the potting compound. This is brought about, in particular, by the use of an appropriately formed mold for molding.
A printed circuit board in the sense of the present disclosure can be referred to, in particular, as a printed circuit card, circuit board or as a printed circuit. The printed circuit board is also referred to as a “PCB”. A printed circuit board in the sense of the present disclosure includes, in particular, an electrically insulating material, for example a dielectric. Conductive connections, the conductor tracks, are arranged on said electrically insulating material. In particular, the conductive connections adhere to the printed circuit board. By way of example, a fiber-reinforced plastic is provided as electrically insulating material. In particular, the conductor tracks are etched from a thin layer of copper. That is to say therefore, in particular, that a printed circuit board in the sense of the present disclosure includes a carrier composed of an electrically insulating material, wherein one or a plurality of conductor tracks formed from copper, for example, are arranged on the carrier. In particular, the printed circuit board includes one or a plurality of plated through holes, so-called vias. The light-emitting diode may be electrically connected to one or a plurality of conductor tracks and/or to one or a plurality of vias.
In another embodiment it is provided that the light-emitting diode is completely embedded or enclosed by molding.
According to one embodiment it is provided that the light-emitting diode is enclosed by molding to an extent such that exclusively the luminous face is no longer enclosed by molding, that is to say remains free. That is to say therefore, in particular, that, in this embodiment, the luminous face remains or is formed free of potting compound. That is to say, in particular, that only the light-emitting face, that is to say the luminous face, is visible in the molded state.
In a further embodiment it is provided that the printed circuit board includes an anchoring structure for anchoring the potting compound on the printed circuit board, such that the potting compound is anchored on the printed circuit board by the anchoring structure. This affords the technical advantage, in particular, that the potting compound or molding compound is held mechanically stably and robustly on the printed circuit board.
In another embodiment it is provided that the anchoring structure includes at least one cutout in which potting compound is received. This affords the technical advantage, in particular, that an even stabler mechanical anchoring is brought about.
In another embodiment it is provided that the cut out is a through hole. That is to say therefore, in particular, that the printed circuit board includes a through hole. This affords the technical advantage, in particular, that an even stabler anchoring of the potting compound on the printed circuit board is brought about.
In another embodiment it is provided that a plurality of cutouts, advantageously a plurality of through holes, are provided. The plurality of cutouts, in particular the plurality of through holes, are formed in particular identically or advantageously differently.
According to a further embodiment it is provided that the anchoring structure includes two opposite edges of the surface which are potted by means of the potting compound. This affords the technical advantage, in particular, that structures of the printed circuit board that are already present are efficiently used as an anchoring structure: here the two opposite edges. Said two opposite edges thus act as an anchor for the potting compound. In particular, as a result, advantageously it is possible to dispense with further anchoring structures; by way of example, it is possible to dispense with a cutout, advantageously a through hole. Consequently, this advantageously obviates the need to additionally include space for such a cutout, for example a through hole, when planning the layout of the printed circuit board. The printed circuit board can thus advantageously be made smaller.
According to another embodiment it is provided that the potting compound includes a mounting face for mounting of a component, said mounting face being formed parallel to the surface. This affords the technical advantage, in particular, that one or a plurality of components can be arranged or mounted onto the potting compound, that is to say more precisely onto the mounting face. Consequently, even further components can be mounted onto the device after molding.
According to another embodiment it is provided that the surface includes a potting-compound-free-section (or a plurality of potting-compound-free-sections) for mounting of a component. This affords the technical advantage, in particular, that even after molding it is possible to mount or arrange components (the singular is intended also always to be inferred) onto the surface of the printed circuit board. Consequently, it is thus advantageously possible subsequently, that is to say after molding, to arrange components onto the printed circuit board.
According to one embodiment it is provided that the component is a lens mount or a reflector. In particular, the component is a lens. In particular, a plurality of components are arranged or mounted onto the mounting face and/or onto the potting-compound-free-section. The plurality of components may be formed identically or, in particular, differently.
According to one embodiment it is provided that the component is arranged or mounted both on the mounting face and on the potting-compound-free-section. That is to say therefore, in particular, that the component itself has a mounting face that corresponds to the geometry and structure of the potting-compound-free-section and of the mounting face, such that the component can be placed or mounted or arranged by its mounting face onto the mounting face of the potting compound and onto the potting-compound-free-section of the surface of the printed circuit board.
In a further embodiment it is provided that as component a lens mount is arranged on the mounting face or respectively the potting-compound-free-section. This affords the technical advantage, in particular, that a lens can be mounted in a simple manner. This then advantageously makes it possible for light emitted by the light-emitting diode to be optically imaged by the lens.
In a further embodiment it is provided that the potting compound includes a reflector section for reflecting light emitted by the diode. That is to say therefore, in particular, that a part of the potting compound forms a reflector. Thus an additional reflector need not necessarily be placed onto the potting compound for the purpose of reflecting the light emitted by the light-emitting diode. Said reflector section is advantageously formed during molding on account of an appropriately shaped mold. A reflector section or a reflector in the sense of the present disclosure is configured, in particular, to reflect the light emitted by means of the light-emitting diode away from the luminous face.
According to a further embodiment it is provided that an anchoring structure for anchoring the potting compound on the printed circuit board is formed on the printed circuit board before molding, such that during molding the potting compound is anchored onto the printed circuit board by the anchoring structure.
In accordance with a further embodiment it is provided that the anchoring structure includes at least one cutout which is formed on the printed circuit board, such that potting compound is received into the cutout during molding.
In a further embodiment it is provided that a mounting face for mounting of a component, said mounting face being parallel to the surface, is formed by means of the potting compound during molding.
According to a further embodiment it is provided that during molding a section of the surface is kept free of potting compound, such that after molding the surface includes a potting-compound-free-section for mounting of a component.
According to another embodiment it is provided that as component a lens mount is arranged onto the mounting face or respectively onto the potting-compound-free-section.
In accordance with another embodiment it is provided that a reflector section for reflecting light emitted by means of the diode is formed by means of the potting compound during molding.
In one embodiment, the diode is formed as a light-emitting diode chip (LED chip).
In a further embodiment, a plurality of diodes are formed per luminous face.
According to another embodiment, a plurality of luminous faces are provided.
In accordance with a further embodiment, a plurality of light sources are provided.
In one embodiment, a conversion layer is arranged on the luminous face of the diode. A surface facing away from the luminous face of the diode is likewise luminous during the operation of the diode on account of the conversion; therefore, this surface of the conversion layer can also be referred to as a luminous face. The conversion layer includes a phosphor, for example.
In one embodiment, the potting compound includes an epoxy resin and/or a silicone. In particular, the potting compound is white. Other colors, too, may advantageously be provided; for example: red, yellow, green, blue, orange, purple, grey or black.
Embodiments regarding the method analogously arise from embodiments regarding the device, and vice versa. That is to say that explanations, technical advantages and features of the device analogously also apply to the method, and vice versa.
The above-described properties, features and advantages of the present disclosure and the way in which they are achieved will become clearer and more clearly understood in association with the following description of the embodiments which are explained in greater detail in association with the drawings.
In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the disclosed embodiments. In the following description, various embodiments described with reference to the following drawings, in which:
Hereinafter, identical reference signs may be used for identical features. Furthermore, it is provided that not all features always have reference signs in the drawings. In particular, a simplified schematic illustration is provided, inter alia. This is intended to be for the sake of better clarity.
The printed circuit board 101 is illustrated in a simplified manner. In this regard, the individual conductor tracks of the printed circuit board 101 are not shown. It is clear to the person skilled in the art, however, that a printed circuit board 101 usually includes one or a plurality of conductor tracks. The printed circuit board 101 is of monolayer or multilayer construction, for example. In particular, the printed circuit board 101 is based on “FR4” or “MCB”. “FR4” denotes a printed circuit board material. “MCB” stands for “Metal Core Board”.
A conversion layer 209 is arranged on the luminous face 205. Said conversion layer 209 converts the light emitted by the LED chip 203 into other light having a different wavelength. By way of example, the conversion layer 209 includes a phosphor. The reference sign 211 points to a surface of the conversion layer 209 which faces away from the luminous face 205 of the LED chip 203. In a plan view and in operation of the LED chip 203, the surface 211 is then also luminous of course. Said surface may therefore likewise be referred to as a luminous face.
In this regard, in accordance with the device 301 it is provided that two (or if necessary also a plurality of) through holes 313 were formed in the printed circuit board 101. Said through holes 313 receive potting compound 305 during molding. Said through holes 313 bring about an anchoring of the potting compound 305 that has at least partly enclosed by molding the LED chip 203 with the conversion layer 209 thereof and also the bonding wire or the bonding wires 207. That is to say that after molding only the surface 211 of the conversion layer 209 is exposed, that is to say is free of potting compound 305. Only this surface is still visible after molding. The further components, in particular the bonding wire or the bonding wires 207 and also the LED chip 203, are no longer visible after molding. The two through holes 313 form an anchoring structure.
As is furthermore shown in
An emission direction of the light emitted by means of the LED chip 203 is identified by an arrow having the reference sign 319. This is also the case in further drawings, but not in all the drawings.
The device 303 does not have through holes 313 like the device 301. Rather, here two opposite edges 307 of the surface 103 form an anchoring structure for the potting compound 305. The two edges 307 are molded by the potting compound 305. In this case, the potting compound 305 furthermore covers lateral surfaces 309 that are formed perpendicularly to the surface 103 and adjacently to the respective edges 307. In the device 303, therefore, the potting compound 305 covers the surface 103 completely apart from the locations already occupied by the LED chip 103 and by the contact area of the bonding wires 207 on the surface 103.
The reference sign 311 points at a surface which, relative to the surface 103, that is to say the mounting surface for an LED chip, is situated opposite (that is to say the rear side of the printed circuit board 101). In an embodiment that is not shown, it may be provided that the potting compound 305 also furthermore at least partly covers the surface 311. That is to say that here the potting compound 305 reaches as it were under the printed circuit board 101 and can thus bring about an even better anchoring of the potting compound 305 on the printed circuit board 101.
In both embodiments, that is to say both in the device 301 and in the device 303, the potting compound 305 has a mounting face 317 formed parallel to the surface 103. In particular, said mounting face 317 is flush with the surface 211 of the conversion layer 209. A further component, for example a reflector or a lens mount, can advantageously be arranged on the mounting face 317.
To summarize,
The potting compound 305 includes an epoxy resin or a silicone, for example.
In accordance with
In accordance with
The reflector 1001 furthermore has reflector walls 1003 which are arranged opposite one another and run toward the surface 211 of the conversion layer 209 in a funnel-shaped fashion.
The reference sign 1507 points at a lifting cylinder including a spring 1509, which lifting cylinder can introduce a molding or a potting compound 1511 into the space or into the cavity that is formed when the two mold tools 1503 and 1505 are placed one on top of the other and enclose the printed circuit board 101. A lifting direction of the lifting cylinder 1507 for introducing the potting compound 1511 is identified by an arrow having the reference sign 1513. In accordance with the chosen shape of the mold tools 1503 and 1505, precisely defined structures can be introduced into the potting compound 1511. By way of example, a reflector structure can be formed and/or advantageously flat and/or planar surfaces. This is shown in
In a manner similar to
The opposite edges of the surface which is embedded by the molding compound 305 are provided as anchoring in the embodiment in accordance with
Both in the case of the arrangement in accordance with
In accordance with
In
The present disclosure thus encompasses the concept, in particular, of combining the strengths of printed circuit board technology with leadframe technology and concepts correspondingly based thereon, while at the same time minimizing the weaknesses. The following advantages can correspondingly be achieved in accordance with the different embodiments:
The flexibility of the designs makes it possible to fulfill customer requests which previously could not be realized by the individual concepts.
Advantages of a PCB substrate (that is to say of a printed circuit board as substrate or carrier) are for example:
Exemplary advantages of molding by molding compound after arranging and electrically connecting the diode:
While the disclosed embodiments have been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the disclosed embodiments as defined by the appended claims. The scope of the disclosed embodiments is thus indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2014 112 540.1 | Sep 2014 | DE | national |
The present application is a national stage entry according to 35 U.S.C. §371 of PCT application No.: PCT/EP2015/069861 filed on Aug. 31, 2015, which claims priority from German application No.: 10 2014 112 540.1 filed on Sep. 1, 2014, and is incorporated herein by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/069861 | 8/31/2015 | WO | 00 |
