Patent Application
20180097154
This application claims priority to German Patent Application Serial No. 10 2016 218 827.5, which was filed Sep. 29, 2016, and is incorporated herein by reference in its entirety.
Various embodiments relate generally to a light emitting component, e.g. a light emitting semiconductor chip component, and also a method for manufacturing such a light emitting component.
Light emitting semiconductor chips, also called light emitting diodes or LEDs for short, constitute a light source having a good efficiency since they convert a large proportion of the required electric current into light. In recent years, illuminants including such light emitting semiconductor chips have been developed which have a similar appearance to conventional incandescent lamps and can also be used in the same way as conventional incandescent lamps. In this case, linear LED emitters are used, in which a plurality of light emitting semiconductor chips are arranged on a common, linear substrate. These LED emitters can also be referred to as LED filaments. In the switched-on state, illuminants including such LED emitters have a similar effect to conventional incandescent lamps.
In this case, however, the individual filaments have to be mounted on a holder and subsequently joined in the desired lamp in a complex and fragile process. Moreover, it can happen that the emission characteristic of such filaments is nonuniform both with regard to the intensity and with regard to the color relative to the azimuth or polar angle of the respective filament.
In various embodiments, a light emitting component is provided. The light emitting component includes a plurality of light emitting semiconductor chips. The semiconductor chips are arranged on at least one carrier. The semiconductor chips are electrically contacted. The light emitting component further includes a converter. The converter is configured to convert light in a first wavelength range, said light being emitted by at least one portion of the light emitting semiconductor chips, at least partly into light in a second wavelength range. The converter is formed separately from the at least one carrier.
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 invention. In the following description, various embodiments of the invention are described with reference to the following drawings, in which:
The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and embodiments in which the invention may be practiced.
The word “exemplary” is used herein to mean “serving as an example, instance, or illustration”. Any embodiment or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or designs.
In addition, electrical contacts 18 are provided at the longitudinal sides of the carrier 12, said contacts projecting beyond the carrier 12. The electrical contacts 18 serve for electrically contacting the light emitting chips 14. The electrical contacts 18 can be secured at the end side of the carrier 12 or partly overlap the surface of the carrier 12 and be secured at the carrier 12 in the overlap region. Along the carrier 12, the chips 14 can be interconnected with one another in various ways, as will also be explained later by way of example with reference to
As is further illustrated in the embodiment in accordance with
The light emitting structure 10 together with a housing 20 forms a light emitting component 1. In this case, the light emitting structure 10 is surrounded by the housing 20 in the embodiment shown according to
It is also conceivable, moreover, for said converter means 22 to include a further converter material, which is formed and provided for converting light in the first or second wavelength range into light in a third wavelength range. Moreover, a further converter means can also be formed, which converts light in the first or second wavelength range into light in a third wavelength range.
The converter means 22 and the housing 20 can be formed integrally with one another. That is to say that the converter means 22 can be formed as part of the housing 20 or at least partly form the housing 20. In the embodiment in
In
In
In the embodiments according to
It is conceivable for further light emitting structures 10 to be introduced into a housing 20, a receiving limit being predefined by the diameter d of the housing 20 and the dimensioning of the light emitting structures 10. In this case, the light emitting structures 10 can be connected in series or in parallel with one another. This enables a flexible adaptation of the light emitting components 1 to the available electrical power supply systems, by targeted arrangement and interconnection of the light emitting structures 10. By arranging light emitting structures 10 in housings 20 which have the same external dimensions e.g. independently of the number of light emitting structures to be received, it is possible for an outer appearance of the light emitting components to be uniform over different wattage ranges.
Moreover, it is conceivable for an additional diffuser means to be formed on, at or in the housing. Such a diffuser means can scatter the light emitted by the light emitting structure and bring about a more homogeneous emission of the light emitting component 1 in this way. In this case, the diffuser means can also be formed integrally with the converter means 22, 222, 224, 226 and/or with the housing 20, 202, 204, 206 and/or with the protective film 16.
In the example in
In the example in
In addition, it is conceivable for the carrier to include or consist of sapphire, glass and/or semitransparent or highly reflective ceramics such as Al2O3, for example.
Moreover, in some embodiments, the chips 14 can be arranged on the carrier 12 or the connection layer 13 not only in a single-row, linear arrangement but also in a plurality of rows or irregularly. The distribution of the chips 14 on the carrier or the connection layer can be effected for example depending on an emission characteristic to be achieved.
It is additionally possible that, in a method process after the light emitting structure 10 has been introduced into the housing 20, 202, 204, 206, a filling material, which can also contain the diffuser means, for example, is introduced into the space enclosed by the housing. In this way, the one or the plurality of light emitting structures can be held or fixed in the housing 20, 202, 204, 206.
In a first process, cf.
In a next process, the matrix 100, as necessary, preferably carrier by carrier, can be singulated or provided with a predetermined breaking location or a perforation in the matrix 100. In a final process, which can be performed during production or after production, before use, singulation by separating the perforation can then in turn be carried out.
Various embodiments may improve at least one of the disadvantages mentioned. In various embodiments, a light emitting component is provided which can be produced in a simplified manner. Moreover, various embodiments provide a method for manufacturing a component in a simplified manner.
A first aspect relates to a light emitting component including a plurality of light emitting semiconductor chips. In this case, the semiconductor chips are arranged on at least one carrier and electrically contacted. Moreover, the light emitting component includes a converter means, wherein the converter means is configured to convert light in a first wavelength range, said light being emitted by at least one portion of the light emitting semiconductor chips, at least partly into light in a second wavelength range. In this case, the converter means is formed separately from the at least one carrier. In various embodiments, the first wavelength range and the second wavelength range do not overlap.
In various embodiments, the conversion means only partly converts the radiation of the LED chips, such that a certain proportion of the radiation of the LED chips passes through the conversion means without being converted. In this way, the light emitting component emits mixed-colored radiation composed of converted and unconverted radiation. In various embodiments, the light emitting component emits mixed-colored radiation having a color locus in the white region of the CIE standard chromaticity diagram.
As a result of the converter means being provided separately from the carrier equipped with semiconductor chips, it is possible to skip a step of applying the converter material during the production of the individual semiconductor chips. This can simplify the production process by virtue of the fact that the converter means can be implemented jointly for all the semiconductor chips after the semiconductor chips have been positioned on a carrier. Moreover, the appearance of a traditional incandescent filament can be better imitated by providing the converter means, for example in the form of a common encapsulation around a semiconductor chip carrier.
The semiconductor chips can be formed in particular as LED chips. The LED chips typically include an epitaxially grown semiconductor layer sequence having an active zone, which generates electromagnetic radiation in a first wavelength range during operation. The electromagnetic radiation generated during the operation of an LED chip is emitted by the LED chip from a primary light exit surface that runs parallel to the semiconductor layers and forms a surface of the semiconductor chip.
The LED chips can be so-called volume emitters, for example. A volume emitting LED chip includes a substrate, on which the semiconductor layer sequence was generally grown epitaxially. The substrate may include or consist of sapphire or silicon carbide, for example. In principle, the substrate can at least include all III/V and II/VI compound semiconductors. In addition, silicon or germanium, for example, is also conceivable. Volume emitting LED chips generally emit the radiation generated in the active zone not just via the primary light exit surface, but also via their side surfaces.
Furthermore, the LED chips can also be thin-film LED chips. Thin-film LED chips include an epitaxially grown semiconductor layer sequence applied on a different carrier than the growth substrate for the semiconductor layer sequence. A mirror layer can be arranged between the semiconductor layer sequence and the carrier, said mirror layer directing radiation of the active zone to the light exit surface. Thin-film LED chips generally do not emit the electromagnetic radiation generated in the active zone during operation via the side surfaces of the carrier, but rather have a substantially Lambertian emission characteristic.
In accordance with one embodiment of the LED filament, a plurality of LED chips are used, which are electrically interconnected with one another in a row in series and/or in parallel. The LED chips can be electrically contacted by means of bond wires, tapes or else lithographically. By way of example, the LED chips can be electrically interconnected with one another in series by means of front-side bond wires.
It is conceivable, moreover, for the LED filament to consist of one or more component parts each including a plurality of light emitting regions. In this case, a substrate may include a plurality of light emitting sections. Such light emitting sections on the substrate can be created for example by the light emitting semiconductor layers being applied on a substrate by means of the known methods. Afterwards, the sections can be produced by structuring the semiconductor layer. In addition, it is likewise conceivable for the light emitting sections to be produced already during the process of growing the semiconductor layer sequence.
The converter means can be formed around the entire emissive surface of the carrier. A greater homogeneity of the emitted and subsequently converted light can be achieved in this way. By virtue of the fact that the light emitted by the semiconductor chips has to cover the same path distance through the separately formed converter means in a radial direction proceeding from the respective chip, the emission of the light and the color temperature thereof can thus be more homogeneous in said radial direction. In various embodiments, a more homogeneous wavelength conversion can take place in all directions in this way.
It is also conceivable in some embodiments of the invention for the converter means to have an inhomogeneous shape, for example an inhomogeneous thickness, or for the converter material to have a predefined distribution in the converter means. In this case, the converter material can be distributed homogeneously but also inhomogeneously in and/or on the converter means. An inhomogeneous emission of light from the respective chips in different spatial directions can be compensated for to the effect that a color temperature, that is to say a conversion proportion of light, is provided approximately identically in all directions proceeding from the individual chip.
In various embodiments, it is conceivable for the converter material to be distributed inhomogeneously in the converter means in such a way that a physical treatment of the converter means, for example by heating or folding, leads to a predefined, e.g. homogeneous, distribution of the converter material when the converter means has the envisaged arrangement around the LED emitter.
In some embodiments, the converter means is formed as a housing. In this case, the housing is dimensioned in such a way that it is suitable for receiving at least one carrier equipped with light emitting semiconductor chips. The carrier can be e.g. a strip-shaped carrier, as is the case for example for a filament-like component. In this case, in some embodiments the housing can be formed as a dimensionally stable component. In this case, in the context of the present invention, dimensionally stable should be understood to mean any material which, on the one hand, can maintain an outer shape by virtue of inherent material properties of the housing. That may also include materials which have a solid or for example liquid or flowable or deformable state depending on the temperature. On the other hand, the housing material must simultaneously be at least partly transmissive to the emitted wavelength ranges of the semiconductor chips. In this way, a carrier equipped with semiconductor chips can be received in the housing and emit light into or through the housing. In this way, the carrier can be protected by the housing. This can reduce the risk of damage to the carrier and/or the semiconductor chips or contamination. Moreover, mounting or receiving of the carrier in the housing can be simplified e.g. by means of a dimensionally stable housing material.
In various embodiments, housings having the same dimensions can be used for different carriers and/or illuminants. In this way, an external appearance of different light emitting components can be identical, independently of the chips or LEDs used.
In various embodiments, the housing can be formed as a cylindrical housing, e.g. having end-side openings which enable access to the interior enclosed by the housing. In the case of such a cylindrical housing, at least one LED emitter, that is to say a carrier occupied by semiconductor chips, can be introduced into the interior of the cylindrical housing. In this case, the receiving may be effected in such a way that the entire carrier with the exception of its two longitudinal end sections is received in the housing. In such embodiments, the terminal contacts for contacting the semiconductor chips arranged on the carrier are e.g. in the region of the two longitudinal end sections of the carrier. In some embodiments, it is also conceivable for contacting to be provided only at one end of the carrier. In these embodiments, it is also conceivable for the housing to have an opening to the interior enclosed thereby only at one end side.
The housing can also be dimensioned in such a way that more than one LED emitter, e.g. two or three LED emitters, can be received in the interior enclosed by the housing. This can make it possible to improve a homogeneity of the emission from the entire component with regard to color temperature and intensity. Moreover, in this way a forward voltage of the component can be adapted to a power supply system voltage in a simplified manner. In this regard, a forward voltage of an LED emitter can be set to approximately 85 V-90 V by corresponding arrangement and wiring of the semiconductor chips on the carrier. Given a power supply system voltage of 230 V, by way of example, two of the LED emitters according to various embodiments may then be connected in series, while the same two LED emitters can be connected in parallel given a power supply system voltage of 110 V. In various embodiments, in this case, light emitting components according to various embodiments are combined in such a way that in total a number of LED emitters which are interconnected in a lamp corresponds to a multiple of two. These are then combined and interconnected with one another in accordance with the power supply system voltage. Moreover, applications for other voltage ranges, such as 12 V, for example, are also conceivable by corresponding alteration of the number and the arrangement of the chips on a filament-like component.
In some embodiments, at least one surface of the converter means includes a converter material suitable for conversion from the first wavelength range to the second wavelength range. That means that a converter material is provided on at least a top side of the converter means. In the case of a cylindrical converter means, for example, this can involve an inner surface of the converter means, that is to say a side of the converter means facing the carrier or carriers. In addition, it is also conceivable for the converter material to be provided on an outer surface of the converter means, that is to say a side of the converter means facing away from the carrier or carriers. In this regard, a process of arranging the converter material on the converter means can be effected after production of the housing and need not already be performed during the production process. This can simplify an adaptation of the converter means to the carriers used. The converter means can thus be produced separately from the light emitting component.
It is also conceivable for the converter means to be formed in a hollow-walled fashion and for a cavity to be at least partly filled with the converter material. In this case, the filling can be homogeneous or inhomogeneous. Additionally or alternatively, the housing may include a material or consist of a material which is mixed and/or interspersed, in particular homogeneously, with the converter material. Integral combination of the housing with the converter means or converter material can allow simplified mounting.
As already explained, the converter means includes at least one converter material which converts light from a first wavelength range into light from a second wavelength range. It is also conceivable for a further converter material to be provided in, on or separately from the converter means, which converts light from the first and/or from the second wavelength range into light from a third wavelength range. In this case, the wavelength ranges can be separate from one another or else, at least partly, overlap one another. A color locus of the emitted light can be set in this way. The second converter material can be formed e.g. on a surface or, similarly to the first converter material, in the converter means or a housing. In this case, provision can also be made of a further converter means, separately from the converter means mentioned, which includes the second converter material. In this case, the second converter means can be formed and arranged in a similar manner to that already explained for the converter means.
The second converter material can in turn be arranged and formed homogeneously or inhomogeneously, in a manner as already explained for the first converter material.
In some embodiments, the converter means may include a glass material. In this case, the converter means can also completely consist of the glass material. In principle, the converter material is transparent or at least partly transparent in a predetermined wavelength range e.g. in the visible range of the electromagnetic spectrum.
In addition, in some embodiments, the converter means can also include or consist of a shrinkable material, in particular a heat shrinkable material. This can enable facilitated mounting of the light emitting component in the converter means. In addition, this can enable protection of the light emitting elements, for example against moisture or contamination. The heat shrinkable material may include or consist of, for example, polyolefins, polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC) and/or polytetrafluoroethene (PTFE) or Teflon. These materials can either be filled or intermixed with particles for wavelength conversion or else be produced in a transparent fashion.
In further embodiments, the converter means includes a film including the phosphor or the phosphors. In this case, the film is arranged around at least one portion of the light emitting semiconductor chips. In this way, a simple formation of the converter means around the light emitting structure can be effected, which can enable a simplified and accelerated production process. In this case, the film can be for example a self-adhesive film, a heat activatable film, which acquires adhesive properties when heat is supplied, or other suitable films. The film can also be secured on the light emitting structure by separate adhesion means, for example by supplying an adhesive layer before the complete enclosure of the light emitting structure.
In further embodiments, it is conceivable, moreover, for the light emitting component to include a diffuser material. The diffuser material can be formed on the converter means and/or in the converter means and/or between the converter means and the at least one carrier. The diffuser material can contribute to the light emitting element having a more homogeneous emission. The diffuser material, if it is formed between the carrier and the converter means, can also contribute to the converter means being illuminated more uniformly by the emitted light. In this way, an evolution of heat in the converter on account of the conversion process can also be distributed more homogeneously in the converter means.
The converter means is advantageously formed for receiving a plurality of carriers equipped with semiconductor chips, or more generally a plurality of light emitting structures. In various embodiments, the converter means can be formed for receiving two or three carriers. In this way, an interconnection and wiring of the light emitting semiconductor chips can already be carried out before final mounting in the converter means and the wired carriers and light emitting semiconductor chips can be arranged jointly in the converter means.
In some embodiments of the light emitting components, the light emitting chips are electrically interconnected with one another in series and/or in parallel. The light emitting chips can be electrically contacted by means of bond wires, tapes or else lithographically. By way of example, the LED chips are electrically interconnected with one another in series by means of front-side bond wires.
The carrier element of the light emitting component may include a first electrical contact location on a first end region of the first main surface. By way of example, the front side of the directly adjacent LED chip can be electrically conductively connected to the contact location by a bond wire. In this case, the first contact location may e.g. be electrically insulated from the carrier element.
It is additionally possible for the LED chips or the carriers having the light emitting chips to be embedded into a protective layer that is free of wavelength-converting properties and serves merely for the protection of the LED chips and/or the mechanical stabilization of the light emitting structure. This can simplify production of LED components according to various embodiments.
The carrier equipped with semiconductor chips may include a sapphire carrier. In this case, the semiconductor chips can preferably be adhesively bonded on the carrier and contacted with one another by means of wire connection.
Alternatively, the carrier equipped with semiconductor chips may include a sapphire substrate, wherein the sapphire substrate e.g. includes metalizations for connecting the semiconductor chips and the semiconductor chips are e.g. secured and contacted on the carrier by means of a solder.
Once again as an alternative, the semiconductor chips can be arranged as light emitting sections on a substrate or auxiliary carrier.
A method according to various embodiments for producing a light emitting component in accordance with one embodiment includes a process according to which a carrier equipped with a plurality of light emitting semiconductor chips is provided. In addition, a converter means is provided, for converting light emitted by at least one portion of the semiconductor chips. The carrier equipped with the semiconductor chips and the converter means are arranged in such a way that the converter means surrounds the carrier and/or the carrier is received in the converter means.
In this context, “surround” means that the converter means projects beyond or overlaps the carrier at least partly in a radial direction proceeding from the carrier directly, that is to say in direct contact, or only indirectly, if appropriate also with intervening layers.
The semiconductor chips can be arranged at regular or irregular distances on the carrier.
In one development of the method, the converter means is a glass cylinder, into which at least one carrier equipped with semiconductor chips is introduced.
Alternatively, the converter means may include a heat shrinkable material. In this case, at least one carrier equipped with semiconductor chips is surrounded by the heat shrinkable converter material. The heat shrinkable converter material is subsequently heated. The heating may be effected in such a way that the heat shrinkable converter material shrinks and contracts, such that it closes, e.g. without any gaps, around the carrier and the light emitting chips arranged thereon. In addition, it is possible to use for this purpose materials which are deformable by sufficient heating and in this way adapt to the contour of the carrier with chips mounted thereon. In various embodiments, the heat shrinkable material can be a material which permanently contracts as a result of the heat treatment.
In once again an alternative method, the converter means is formed as a film including a converter material. In this case, at least one carrier is arranged by a first surface on the converter material and a second surface of the carrier is then covered with the converter material.
A plurality of carriers can also be arranged on the film including the converter material. In this case, all the carriers are covered with the film, e.g. with the same film. After the encapsulation of the plurality of carriers, the carriers encapsulated with the film are then finally singulated.
In this case, both such a film and such a heat shrinkable material may e.g. be formed in such a way that the converter material is embedded into the film material and respectively into the heat shrinkable material. Other embodiments are also possible, of course, as mentioned in the context of the converter means.
By way of example, one of the following materials is suitable for the phosphor particles or the converter particles, the enumeration not being exhaustive, but rather only of exemplary nature: garnets doped with rare earths, alkaline earth metal sulfides doped with rare earths, thiogallates doped with rare earths, aluminates doped with rare earths, silicates doped with rare earths, orthosilicates doped with rare earths, chlorosilicates doped with rare earths, alkaline earth metal silicon nitrides doped with rare earths, oxynitrides doped with rare earths, aluminum oxynitrides doped with rare earths, silicon nitrides doped with rare earths, sialons doped with rare earths. Further phosphors known to the person skilled in the art are likewise conceivable.
While the invention has 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 invention as defined by the appended claims. The scope of the invention 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 2016 218 827.5 | Sep 2016 | DE | national |
