WO2019141374A1 - Method for producing a plurality of conversion elements, conversion element and optoelectronic component - Google Patents

Method for producing a plurality of conversion elements, conversion element and optoelectronic component Download PDF

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Publication number
WO2019141374A1
WO2019141374A1 PCT/EP2018/051334 EP2018051334W WO2019141374A1 WO 2019141374 A1 WO2019141374 A1 WO 2019141374A1 EP 2018051334 W EP2018051334 W EP 2018051334W WO 2019141374 A1 WO2019141374 A1 WO 2019141374A1
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WO
WIPO (PCT)
Prior art keywords
mold
conversion
conversion element
reflective material
reflective
Prior art date
Application number
PCT/EP2018/051334
Other languages
French (fr)
Inventor
Hui Chiang TEOH
Wai-Choo CHAI
Original Assignee
Osram Opto Semiconductors Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Osram Opto Semiconductors Gmbh filed Critical Osram Opto Semiconductors Gmbh
Priority to PCT/EP2018/051334 priority Critical patent/WO2019141374A1/en
Publication of WO2019141374A1 publication Critical patent/WO2019141374A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/50—Wavelength conversion elements
    • H01L33/505—Wavelength conversion elements characterised by the shape, e.g. plate or foil
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/44—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the coatings, e.g. passivation layer or anti-reflective coating
    • H01L33/46—Reflective coating, e.g. dielectric Bragg reflector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
    • H01L2933/0008—Processes
    • H01L2933/0033—Processes relating to semiconductor body packages
    • H01L2933/0041—Processes relating to semiconductor body packages relating to wavelength conversion elements

Definitions

  • a method for producing a plurality of conversion elements is provided. Furthermore, a conversion element and an
  • conversion element and an optoelectronic component comprising such a conversion element.
  • a method for producing a plurality of conversion elements is provided.
  • the conversion elements are of wavelength
  • wavelength conversion is herein understood to mean in particular the conversion of electromagnetic radiation of one particular wavelength range into electromagnetic radiation of another, preferably longer- wave, wavelength range.
  • the conversion elements comprise, for example, particles of a luminescence conversion material.
  • the method comprises the step of providing a first mold, having an opening.
  • the first mold for example, extends along a main direction of extent which is directed from a first end part to a second end part of the first mold.
  • the opening for example, face each other, connected by at least one side face of the first mold.
  • the opening for example, extends from the first end part to the second end part of the first mold.
  • the opening for example, penetrates the first mold completely.
  • the opening encloses a first inner volume.
  • the first and the second end part of the first mold for example, are formed circular, oval or rectangular.
  • a cross- sectional area perpendicular to the main direction of extent of the opening may be formed, for example, circular, oval or rectangular .
  • the at least one side face of the first mold comprises an inner side facing the opening, and an outer side facing away from the opening.
  • the inner and outer sides of the first mold may have a constant distance to each other, perpendicular to the main direction of extent. That is to say, the fist mold can have a wall of constant thickness.
  • the method comprises the step of providing a second mold.
  • the second mold extends along the main direction of extent which is directed from a first end part to a second end part of the second mold, connected by an outer surface of the second mold.
  • a cross-sectional area perpendicular to a main direction of extent is smaller than a cross-sectional area of the first mold perpendicular to the main direction of extent.
  • the second mold may be, for example, larger than the first mold along the main direction of extent.
  • the first and the second end part of the second mold for example, are formed circular, oval or rectangular.
  • a cross-sectional area perpendicular to the main direction of extent of the second mold may be formed, for example, circular, oval or rectangular .
  • the method comprises the step of inserting the second mold in the first mold. Due to the smaller cross-sectional area of the second mold compared to the cross-sectional area of the first mold, the second mold fits in the first mold.
  • the second mold may be inserted into the opening of the first mold.
  • the first mold for example, penetrates the opening completely.
  • a volume of the second mold which terminates flush with the first end part and the second end part of the first mold is defined as a second inner volume.
  • the second inner volume is smaller than the first inner volume.
  • the method comprises the step of filling a first volume between an inner surface of the first mold and an outer surface of the second mold with a reflective material.
  • the first volume is, for example, defined by the first inner volume of the opening from which the second inner volume of the second mold is subtracted.
  • the inner surface of the first mold and the outer surface of the second mold face each other.
  • the inner surface of the first mold and the outer surface of the second mold define the first volume.
  • the reflective material is, for example, in direct and immediate contact to the inner surface of the first mold and the outer surface of the second mold.
  • the surface of the first and/or the second end part of the first mold terminates flush with a surface of a first and/or second end part of the reflective material, connected by a side face, for example.
  • the surfaces of the first and the second end parts of the first mold are free of the reflective material.
  • the first and the second end parts of the first mold are substantially free of the reflective material. Substantially free means that small quantities of the reflective material could be present on the first and the second end parts of the first mold.
  • the reflective material has, for example, a thickness being constant parallel to the main direction of extent.
  • the inner surface of the first mold and the outer surface of the second mold for example, have a constant distance parallel to the main direction of extent.
  • the reflective material comprises, for example, a matrix material in which radiation-reflective particles are
  • the matrix material may be, for example, a resin such as an epoxy or a silicone, or a mixture of these
  • the radiation-reflective particles are, for example, titanium oxide particles.
  • the method comprises the step of removing the second mold.
  • the second mold is, for example, extracted from the opening of the first mold, thus forming a further opening, which is free of the second mold.
  • the further opening for example, extends from the first end part to the second end part of the first mold.
  • the further opening for example, penetrates the arrangement of the first mold and the reflective material completely.
  • the further opening encloses the second inner volume.
  • removing the second mold reveals the second inner volume, which is free of the second mold.
  • the method comprises the step of filling a second volume with a conversion material in place of the removed second mold.
  • the second volume is, for example, defined by the first inner volume from which the first volume is subtracted.
  • the second volume is equal to the volume the second mold occupies in the first mold. This means that the second volume is equal to the second inner volume.
  • the conversion material is, for example, introduced into the further opening, which is, for example, the second volume.
  • the conversion material for example, fills the opening completely.
  • the conversion material fills the opening such that a surface of a top part and a surface of a bottom part of the conversion material, connected by a side face, terminate flush with the surface of the first and/or the second end part of the first mold. Further the surface of the bottom and/or top part of the conversion material
  • the side face of the conversion material is, for example, in direct and immediate contact to the side face of the reflective material .
  • the surfaces of the first and the second end parts of the first mold and of the first and the second end parts of the reflective material are free of the conversion material.
  • the first and the second end parts of the first mold and the first and the second end parts of the reflective material are substantially free of the conversion material. Substantially free means that small quantities of the conversion material could be present on the first and the second end parts of the first mold and on the first and the second end parts of the reflective material.
  • the conversion material comprises, for example, a matrix material and luminescence conversion particles.
  • the matrix material for example, is a resin such as an epoxy or a silicone, or a mixture of these materials.
  • the luminescence conversion particles impart the wavelength-converting
  • rare-earth-doped garnets rare-earth-doped garnets, rare-earth-doped
  • alkaline earth sulfides rare-earth-doped thiogallates , rare- earth-doped silicates, rare-earth-doped orthosilicates, rare- earth-doped chlorosilicates , rare-earth-doped alkaline-earth- silicon nitrides, rare-earth-doped oxynitrides, rare-earth- doped aluminum oxynitrides, rare-earth-doped silicon
  • nitrides rare-earth-doped sialons, quantum dots. These materials may also be used without a matrix material and may be applied directly.
  • the conversion element for example, consists of one of these materials.
  • the method comprises the step of removing the first mold.
  • the first mold is, for example, detracted from the reflective material.
  • the reflective material is free of the first mold after removing.
  • the reflective material then protects the conversion material from, for example, chemical damage.
  • the reflective material also protects the conversion material against mechanical damage during further processing steps.
  • the method comprises the step of separating the arrangement of the reflective material and the conversion material into a plurality of conversion elements.
  • the arrangement of the reflective material in the conversion material is, for example, separated along cuts transverse to the main direction of extent.
  • the cuts are perpendicular to the main direction of extent.
  • the conversion elements comprise a top surface and a bottom surface connected by a side face.
  • the side face is formed by the reflective material which covers the side face of the conversion material, which connects a top surface and a bottom surface of the conversion material.
  • the top and bottom surfaces of the conversion material are free of the reflective material, increasing the efficiency of the conversion element.
  • the method for producing a plurality of conversion elements comprises the steps of providing a first mold, having an opening, providing a second mold, and inserting the second mold in the first mold. Further steps are filling a first volume between an inner surface of the first mold and an outer surface of the second mold with a reflective material, removing the second mold, filling a second volume with a conversion material in place of the removed second mold, removing the first mold, and separating the arrangement of the reflective material and the conversion material into a plurality of conversion elements.
  • the method for producing a plurality of conversion elements described here makes use, inter alia, of the idea that the reflective material surrounds the side faces of the
  • the reflective material surrounding the side faces of a conversion material can overflow top and bottom surfaces of a conversion element due to production reasons.
  • the reflective material on the top and bottom surfaces hinders the light extraction as well as the light to be injected in the conversion material.
  • the plurality of conversion elements is, inter alia, to produce an elongated tube comprising the conversion material in its core, covered by the reflective material on the side face of the conversion material.
  • the tube can be separated into single conversion elements by cutting the tube transverse to the elongation direction.
  • the resulting conversion elements comprise top and bottom surfaces, free of the reflective material.
  • the conversion element can then be applied, for example, to a surface-emitting radiation-emitting
  • the reflective material solely surrounds the side faces of a conversion material, this leads, for example, to a reduction of blue light leakage due to side emissions of the semiconductor chip. Moreover, a plurality of conversion elements can be produced while having only one single dispensing process for the reflective
  • this may reduce production costs.
  • a bottom surface of the second mold seals a bottom surface of the opening.
  • a bottom part of the second mold which is not inserted into the opening of the first mold has a cross-sectional area being bigger than the cross-sectional area of the second mold which is inserted in the opening of the first mold.
  • an outer side of the bottom part of the second mold terminates flush with the outer side of the first mold, or is bigger than the outer side of the first mold.
  • the cross-sectional area of the bottom part of the second mold perpendicular to the main direction of extent is equal to the cross-sectional area of the first mold perpendicular to the main direction of extent.
  • the cross-sectional area of the bottom part of the second mold perpendicular to the main direction of extent may be bigger than the cross-sectional area of the first mold perpendicular to the main direction of extent.
  • the bottom surface, which faces the first mold, of the bottom part of the second mold may be, for example, in direct and immediate contact to the surface of the first or second end part of the first mold.
  • the direct contact of the bottom surface and the surface of the first or second end part of the first mold is impermeable, for example, to the reflective material.
  • the bottom surface of the second mold seals the bottom surface of the opening.
  • the contact is impermeable or substantially
  • impermeable means that small quantities of the reflective material could leak out of the contact.
  • the method comprises the step wherein, before removing the first mold, the conversion material is cured.
  • the reflective material is present in a flowable form to fill the first volume between the inner surface of the first mold and the outer surface of the second mold with the reflective material.
  • the reflective material for example, is cured by means of annealing or a UV treatment.
  • the method comprises the step wherein, before removing the first mold, the conversion material is cured.
  • the conversion material is present in a flowable form to fill the second volume with the conversion material in place of the removed second mold.
  • material for example, is cured by means of annealing or a UV treatment .
  • the method comprises the step wherein, before filling the second volume with the conversion material, a further opening of the first mold is sealed with a cap.
  • the cap comprises, for example, two parts.
  • a bottom part for example, has a bigger cross-sectional area perpendicular to the main direction of extent than the cross- sectional area of a further opening perpendicular to the main direction of extent.
  • a side face of the bottom part of the cap for example, terminates flush with the outer side face of the first mold.
  • a top surface, which is connected by the side face to a bottom face, of the bottom part of the cap may be, for example, in direct and immediate contact to the surface of the first or second end part of the first mold.
  • the direct contact of the top surface of the bottom part of the cap and the surface of the first or second end part of the first mold is impermeable, for example, to the conversion material.
  • the cap seals the opening at the first or second end part of the first mold.
  • the contact is
  • Substantially impermeable means that small quantities of the conversion material could leak out of the contact.
  • the second part of the cap is, for example, a small elevation on top of the bottom part of the cap.
  • the height of the elevation is, for example, small compared to the size of the arrangement along the main direction of extent.
  • the cross- sectional area of the elevation perpendicular to the main direction of extent is, for example, equal to or smaller than the cross-sectional area of the opening of the first mold perpendicular to the main direction of extent.
  • elevation for example, may be inserted into the opening of the first mold.
  • the elevation ensures that the cap does not get displaced during the following method steps.
  • At least one of the following components contains or consists of
  • Polytetrafluoroethylene the first mold, the second mold, the cap. If the components comprise Polytetrafluoroethylene, at least part of their surfaces are formed of or coated with Polytetrafluoroethylene . For example, the components
  • PTFE polytetrafluoroethylene
  • Teflon Teflon
  • the components do not react with the reflective material and the conversion material.
  • the reflective material and the conversion material do not adhere to the components containing or consisting of Polytetrafluoroethylene .
  • the components may be removed easily from the cured reflective material and the cured conversion material.
  • the components consisting of PTFE exhibit flexible mechanical properties.
  • the components may be rolled up.
  • the method comprises the step: before separating the arrangement, the cap is removed.
  • the cap is, for example, detracted from the reflective material, the conversion material and the first mold.
  • the reflective material, the conversion material and the first mold are free of the cap on a side where the cap was applied .
  • conversion elements are separated by sawing.
  • the conversion elements are separated, for example, by means of sawing, using a sawing blade, wire or chain, for example.
  • the so produced conversion elements have a roughening on the top surface and the bottom surface of the conversion element.
  • the roughening reduces the probability of total reflection by the conversion material.
  • a conversion element is provided.
  • the conversion element can be produced by the method for producing a plurality of conversion elements described herein before.
  • a conversion element described here may be produced by the method described here or is produced by the described method. All features disclosed in connection with the method for producing a plurality of conversion elements are therefore also disclosed in connection with the
  • the conversion element comprises a conversion material.
  • the conversion material converts electromagnetic radiation into
  • the conversion material has a main extension plane parallel to a top surface and a bottom surface of the conversion material.
  • a side surface of the conversion material connects the top surface and the bottom surface.
  • the conversion element comprises a reflective material.
  • the reflective material for example, is formed to be reflective for the electromagnetic radiation and the converted electromagnetic radiation.
  • the reflective material covers the side face of the conversion material completely. Further, the reflective material is in direct and immediate contact to the side face of the conversion material. A top surface and a bottom surface of the reflective material terminate flush with the top surface and the bottom surface of the conversion
  • the top surface and the bottom surface of the conversion material are free of a reflective material. Within a manufacturing tolerance, for example, the top surface and the bottom surface of the conversion material are
  • substantially free of the reflective material means that small quantities of the reflective material could be present on the top surface and the bottom surface of the conversion material.
  • a top surface and a bottom surface of the conversion element comprise traces of a separation step.
  • the conversion elements are, for example, separated along cuts parallel to the main extension plane. Since the conversion elements are separated, for example, by means of sawing, creating the top and bottom surfaces of the conversion elements, the top and the bottom surfaces comprise traces of the sawing process like, for example, sawing marks. This means that the top and bottom surfaces of the conversion material and the reflective material comprise the traces of the separation step.
  • the reflective material comprises a matrix material and radiation-reflective
  • the reflective material comprises, for example, the matrix material in which the radiation-reflective
  • the matrix material may be, for example, a resin such as an epoxy or a silicone, or a mixture of these materials.
  • the radiation-reflective particles are, for example, titanium oxide particles.
  • the reflective material for example, has a reflectivity of at least 90% for electromagnetic radiation in the visible range. For instance, the reflective material is white.
  • the conversion material is formed to convert electromagnetic radiation of a first wavelength range into electromagnetic radiation of a second wavelength range. That is, the conversion element is of wavelength-converting configuration.
  • the term "wavelength conversion” is, for example, a conversion of electromagnetic radiation of the first wavelength range into electromagnetic radiation of the second wavelength range, for example being a longer wave.
  • electromagnetic radiation of the first wavelength range is absorbed by a wavelength-converting element, converted by electronic processes at an atomic and/or molecular level into electromagnetic radiation of the second wavelength range and reemitted.
  • the term “wavelength conversion” does not mean mere scattering or merely absorption of
  • the conversion material comprises a matrix material and luminescence conversion particles.
  • the matrix material for example, is a resin such as an epoxy or a silicone, or a mixture of these materials.
  • the luminescence conversion particles impart the wavelength converting properties to the conversion material and thus to the conversion element.
  • one of the following materials is suitable for the luminescence conversion
  • rare-earth-doped garnets rare-earth-doped garnets, rare-earth-doped
  • alkaline earth sulfides rare-earth-doped thiogallates , rare- earth-doped silicates, rare-earth-doped orthosilicates, rare- earth-doped chlorosilicates , rare-earth-doped alkaline-earth- silicon nitrides, rare-earth-doped oxynitrides, rare-earth- doped aluminum oxynitrides, rare-earth-doped silicon
  • nitrides rare-earth-doped sialons, quantum dots. These materials may also be used without a matrix material and may be applied directly.
  • the conversion element for example, consists of one of these materials.
  • the matrix material of the reflective material and the matrix material of the conversion material consist of or contain the same materials.
  • the matrix materials for example, are a resin such as an epoxy or a silicone, or a mixture of these materials.
  • the two matrix materials may have, for example, the same thermal expansion coefficient.
  • traces of a separation step are in the form of a roughening of the top surface and the bottom surface of the conversion element. Since the
  • the separation step is achieved, for example, by means of sawing, using a sawing blade, the top surface and the bottom surface of the conversion element are roughened, leading to a
  • the roughening reduces the probability of total reflection at the top surface and the bottom surface of the conversion element.
  • an optoelectronic component is provided.
  • the optoelectronic component may comprise a conversion element, which can be produced by the method for producing a plurality of conversion elements described herein before. All features disclosed in connection with the method for producing a plurality of conversion elements and the conversion element are therefore also disclosed in connection with the optoelectronic component and vice versa.
  • the component comprises a semiconductor chip.
  • the semiconductor chip comprises a semiconductor body.
  • the semiconductor body is, for example, a semiconductor body grown epitaxially.
  • the semiconductor body comprises an n- conducting region, an active region provided for generating electromagnetic radiation, and a p-conducting region.
  • the semiconductor body In the active region of the semiconductor body, primary electromagnetic radiation in the spectral range between UV radiation and infrared radiation, in particular in the spectral range of visible light, is generated for example during operation.
  • the semiconductor body is based for example on a III-V semiconductor material, for example on a nitride compound semiconductor material.
  • the component comprises a here described conversion element.
  • the conversion element is formed to convert the primary
  • electromagnetic radiation produced by the semiconductor chip during operation, into, for example, longer-wavelength secondary radiation.
  • the conversion element is placed on an emission surface of the semiconductor chip.
  • the conversion element is glued to the semiconductor chip or the conversion element is fixed to a housing of the semiconductor chip.
  • the primary electromagnetic radiation generated during operation of the semiconductor chip leaves the semiconductor body, for example, at least partly via the emission surface of the semiconductor chip, being for example a top or bottom surface of the semiconductor chip.
  • the conversion element is placed on the top or bottom surface of the semiconductor chip; thus, the primary electromagnetic radiation may be converted by means of the conversion element.
  • a cross-sectional area perpendicular to the main direction of extent of the emission surface of the semiconductor chip may be, for example, bigger or equal in size compared to the cross-sectional area perpendicular to the main direction of extent of the conversion material.
  • the primary electromagnetic radiation emitted during operation leaves the top or bottom surface of the semiconductor chip.
  • This primary electromagnetic radiation is converted into secondary radiation.
  • the reflective layer of the conversion element for example, leads to a reflection of the primary and
  • the primary electromagnetic radiation is reflected again and enters the conversion material again.
  • the remaining primary electromagnetic radiation is converted again.
  • the primary and secondary radiations are directed by means of the reflective layer, for example, in the direction of a light-emitting surface of the
  • FIGS. 8A and 8B schematic representations of an embodiment of a conversion element described herein
  • FIGS 9A and 9B schematic representations of exemplary embodiments of an optoelectronic component. Identical, similar or identically acting elements are
  • a first mold 2 is
  • the first mold 2 is of the form of a tube, having an opening 22.
  • the opening 22 penetrates the first mold 2 completely.
  • the opening 22 defines a first inner volume.
  • the first mold 2 contains or consists of PTFE.
  • a second mold 3 is provided.
  • the second mold 3 is of the form of a pillar, having a bottom part 33 and a top part 34.
  • the cross-sectional area of the bottom part 33 of the second mold 3 perpendicular to a main direction of extent is bigger than the cross-sectional area of the top part 34 of the second mold 3.
  • the cross- sectional area of the top part 34 of the second mold 3 perpendicular to the main direction of extent is smaller than a cross-sectional area of the first mold 2 perpendicular to the main direction of extent.
  • a first end part of the second mold 3b and a second end part of the second mold 3c face each other.
  • the second mold 3 may be larger than the first mold 2 along the main direction of extent.
  • the length of the first mold 2 is the distance between a first end part 2b and a second end part 2c of the first mold 2.
  • the second mold 3 contains or consists of PTFE.
  • the second mold 3 is inserted in the first mold 2, as shown in Figure 2.
  • the first mold 2 penetrates the opening 22 completely.
  • a first volume 2d is produced, being the volume between an inner surface of the first mold 2a and an outer surface of the second mold 3a over the length of the first mold 2.
  • the first volume 2d is the first inner volume minus the second inner volume.
  • the inner surface of the first mold 2a and the outer surface of the second mold 3a have a constant distance parallel to the main direction of extent.
  • an outer surface of the bottom part 33 of the second mold 3 terminates flush with an outer surface of the first mold 2.
  • the cross-sectional area of the bottom part of the second mold 33 is equal to the cross-sectional area of the first mold.
  • a top surface of the bottom part of the second mold 33 is in direct and immediate contact to a surface of the second end part 2c of the first mold 2.
  • the first inner volume is filled with a reflective material 4.
  • the reflective material 4 terminates flush with the first and the second end parts 2b and 2c of the first mold.
  • the second mold 3 is removed.
  • removing the second mold 3 reveals a further opening 23, defining the second inner volume.
  • the second mold 3 contains or consists of PTFE, which does not react with the reflective material 4 while being in direct and immediate contact with the second mold 3.
  • the reflective material 4 does not adhere to the second mold 3 and the second mold 3 can be removed easily.
  • a cap 5 is provided.
  • the cap 5 comprises two parts. A bottom part 55 and a top part 56.
  • the bottom part of the cap 55 has a bigger cross- sectional area than the cross-sectional area of the further opening 23 of the first mold 2.
  • the cross-sectional area of the bottom part of the cap 55 has the same size than the cross-sectional area of the first mold 2.
  • the top part of the cap 56 is a small elevation on top of the bottom part of the cap 55.
  • the cross-sectional area of the top part of the cap 56 is smaller than the cross-sectional area of the further opening 23 of the first mold 2.
  • the cap is arranged on the second end part of the first mold 2c.
  • the top part of the cap 56 is inserted into the further opening 23 of the first mold 2 and ensures that the cap 5 does not get displaced during the following processing step.
  • a top surface 5a of the bottom part 55 of the cap is in direct contact with a surface of the second end part of the first mold 2c.
  • the further opening 23 of the first mold on the second end part 2c is sealed with the cap 5.
  • a conversion material 6 is filled in the second volume 3d in place of the removed second mold 3.
  • the second volume 3d is here the first inner volume minus the first volume 2d.
  • the conversion material 6 fills the further opening 23 completely.
  • the conversion material 6 fills the further opening 23 such that the top surface 6a and the bottom surface of the conversion material 6 terminate flush with the first and the second end parts 2b and 2c of the first mold 2.
  • the first mold 2 is removed.
  • the first mold 2 contains or consists of PTFE, which does not react with the reflective material 4 while being in direct and immediate contact with the first mold 2.
  • the reflective material 4 does not adhere to the first mold 2 and the first mold 2 can be removed easily.
  • the reflective material 4 is free of the first mold 2 after removing.
  • the reflective material 4 covers a circumferential surface of the conversion material 6.
  • the reflective material 4 then protects the conversion material 6 from chemical damage.
  • the reflective material 4 also protects the
  • conversion elements 1 are separated, for example, by means of sawing, using a sawing blade, for example.
  • a conversion element 1 comprises a conversion material 6 and a reflective material 4.
  • the reflective material 4 surrounds the conversion
  • reflective material 4 is in direct and immediate contact to the side face of the conversion material 6.
  • a top surface and a bottom surface of the conversion material 6 terminate flush with a top surface and a bottom surface of the reflective material 4. Further, the top and bottom surfaces of the conversion material 6 are free of the
  • the conversion element 1 has a main extension plane parallel to the top and bottom surfaces of the conversion material 6 and the reflective material 4.
  • conversion element 1 in the main extension plane is a circle, and also the conversion material 6 and the reflective
  • material 4 are of circular form.
  • a top surface la and a bottom surface lb of the conversion element 1 show traces of a separation step 8, for example a roughening due to the separation step.
  • conversion element 1 is shown.
  • the features of the embodiment according to Figure 8A can be applied to the embodiment of the conversion element according to Figure 8B.
  • a difference to the embodiment according to Figure 8A is that the form of the conversion element 1 in the main extension plane is a rectangle and also the conversion material 6 and the
  • reflective material 4 are of rectangular form. With reference to Figures 9A and 9B, exemplary embodiments of a here described optoelectronic component are shown.
  • the optoelectronic component 10 comprises a conversion element 1 and a semiconductor chip 9.
  • the conversion element 1 is placed on an emission surface of the semiconductor chip 9.
  • the conversion elements 1 have, for example, the same features as described in
  • semiconductor chip 9 is equal in size compared to the cross- sectional area perpendicular to the main direction of extent of the conversion material 6.

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Abstract

In at least one embodiment the method for producing a plurality of conversion elements (1) comprises the steps of: - providing a first mold (2), having an opening (22), - providing a second mold (3), - inserting the second mold (3) in the first mold (2), - filling a first volume (2d) between an inner surface of the first mold (2a) and an outer surface of the second mold (3a) with a reflective material (4), - removing the second mold (3), - filling a second volume (3d) with a conversion material (6) in place of the removed second mold (3), - removing the first mold (2), - separating the arrangement of the reflective material (4) and the conversion material (6) into a plurality of conversion elements (1).

Description

Description
METHOD FOR PRODUCING A PLURALITY OF CONVERSION ELEMENTS, CONVERSION ELEMENT AND OPTOELECTRONIC COMPONENT
A method for producing a plurality of conversion elements is provided. Furthermore, a conversion element and an
optoelectronic component is provided.
It is an object of the present application to provide a method for producing a plurality of conversion elements by means of which a conversion element may be produced cost- efficiently. It is further intended to provide such a
conversion element and an optoelectronic component comprising such a conversion element.
A method for producing a plurality of conversion elements is provided. The conversion elements are of wavelength
converting configuration. The term "wavelength conversion" is herein understood to mean in particular the conversion of electromagnetic radiation of one particular wavelength range into electromagnetic radiation of another, preferably longer- wave, wavelength range. For this purpose, the conversion elements comprise, for example, particles of a luminescence conversion material.
According to at least one aspect, the method comprises the step of providing a first mold, having an opening. The first mold, for example, extends along a main direction of extent which is directed from a first end part to a second end part of the first mold. A surface of the first end part and a surface of the second end part of the first mold, for
example, face each other, connected by at least one side face of the first mold. The opening, for example, extends from the first end part to the second end part of the first mold. The opening, for example, penetrates the first mold completely. Hereby the opening encloses a first inner volume. The first and the second end part of the first mold, for example, are formed circular, oval or rectangular. Further, a cross- sectional area perpendicular to the main direction of extent of the opening may be formed, for example, circular, oval or rectangular .
Thus, the at least one side face of the first mold comprises an inner side facing the opening, and an outer side facing away from the opening. For example, the inner and outer sides of the first mold may have a constant distance to each other, perpendicular to the main direction of extent. That is to say, the fist mold can have a wall of constant thickness.
According to at least one aspect, the method comprises the step of providing a second mold. The second mold extends along the main direction of extent which is directed from a first end part to a second end part of the second mold, connected by an outer surface of the second mold. For
example, a cross-sectional area perpendicular to a main direction of extent is smaller than a cross-sectional area of the first mold perpendicular to the main direction of extent. The second mold may be, for example, larger than the first mold along the main direction of extent. The first and the second end part of the second mold, for example, are formed circular, oval or rectangular. Further, a cross-sectional area perpendicular to the main direction of extent of the second mold may be formed, for example, circular, oval or rectangular . According to at least one aspect, the method comprises the step of inserting the second mold in the first mold. Due to the smaller cross-sectional area of the second mold compared to the cross-sectional area of the first mold, the second mold fits in the first mold. Thus, the second mold may be inserted into the opening of the first mold. The first mold, for example, penetrates the opening completely. For example it is possible that the first end part of the second mold projects beyond the first end part of the first mold, and the second end part of the second mold projects beyond the second end part of the first mold. A volume of the second mold which terminates flush with the first end part and the second end part of the first mold is defined as a second inner volume. For example, the second inner volume is smaller than the first inner volume.
According to at least one aspect, the method comprises the step of filling a first volume between an inner surface of the first mold and an outer surface of the second mold with a reflective material. The first volume is, for example, defined by the first inner volume of the opening from which the second inner volume of the second mold is subtracted. For example, the inner surface of the first mold and the outer surface of the second mold face each other. In connection with the first and second end parts of the first mold, the inner surface of the first mold and the outer surface of the second mold define the first volume. The reflective material is, for example, in direct and immediate contact to the inner surface of the first mold and the outer surface of the second mold. Further the surface of the first and/or the second end part of the first mold terminates flush with a surface of a first and/or second end part of the reflective material, connected by a side face, for example. For example, the surfaces of the first and the second end parts of the first mold are free of the reflective material. Within a manufacturing tolerance, for example, the first and the second end parts of the first mold are substantially free of the reflective material. Substantially free means that small quantities of the reflective material could be present on the first and the second end parts of the first mold.
The reflective material has, for example, a thickness being constant parallel to the main direction of extent. Thus, the inner surface of the first mold and the outer surface of the second mold, for example, have a constant distance parallel to the main direction of extent.
The reflective material comprises, for example, a matrix material in which radiation-reflective particles are
introduced. The matrix material may be, for example, a resin such as an epoxy or a silicone, or a mixture of these
materials. The radiation-reflective particles are, for example, titanium oxide particles.
According to at least one aspect, the method comprises the step of removing the second mold. The second mold is, for example, extracted from the opening of the first mold, thus forming a further opening, which is free of the second mold. The further opening, for example, extends from the first end part to the second end part of the first mold. The further opening, for example, penetrates the arrangement of the first mold and the reflective material completely. Hereby the further opening encloses the second inner volume. Thus, removing the second mold reveals the second inner volume, which is free of the second mold. According to at least one aspect, the method comprises the step of filling a second volume with a conversion material in place of the removed second mold. The second volume is, for example, defined by the first inner volume from which the first volume is subtracted. The second volume is equal to the volume the second mold occupies in the first mold. This means that the second volume is equal to the second inner volume. The conversion material is, for example, introduced into the further opening, which is, for example, the second volume.
The conversion material, for example, fills the opening completely. For example, the conversion material fills the opening such that a surface of a top part and a surface of a bottom part of the conversion material, connected by a side face, terminate flush with the surface of the first and/or the second end part of the first mold. Further the surface of the bottom and/or top part of the conversion material
terminates flush with the surface of the first and/or second end part of the reflective material, for example. The side face of the conversion material is, for example, in direct and immediate contact to the side face of the reflective material .
For example, the surfaces of the first and the second end parts of the first mold and of the first and the second end parts of the reflective material are free of the conversion material. Within a manufacturing tolerance, for example, the first and the second end parts of the first mold and the first and the second end parts of the reflective material are substantially free of the conversion material. Substantially free means that small quantities of the conversion material could be present on the first and the second end parts of the first mold and on the first and the second end parts of the reflective material.
The conversion material comprises, for example, a matrix material and luminescence conversion particles. The matrix material, for example, is a resin such as an epoxy or a silicone, or a mixture of these materials. The luminescence conversion particles impart the wavelength-converting
properties to the conversion material and thus to the
conversion element. For example, one of the following
materials is suitable for the luminescence conversion
particles: rare-earth-doped garnets, rare-earth-doped
alkaline earth sulfides, rare-earth-doped thiogallates , rare- earth-doped silicates, rare-earth-doped orthosilicates, rare- earth-doped chlorosilicates , rare-earth-doped alkaline-earth- silicon nitrides, rare-earth-doped oxynitrides, rare-earth- doped aluminum oxynitrides, rare-earth-doped silicon
nitrides, rare-earth-doped sialons, quantum dots. These materials may also be used without a matrix material and may be applied directly. The conversion element, for example, consists of one of these materials.
According to at least one aspect, the method comprises the step of removing the first mold. The first mold is, for example, detracted from the reflective material. Thus, the reflective material is free of the first mold after removing. The reflective material then protects the conversion material from, for example, chemical damage. The reflective material also protects the conversion material against mechanical damage during further processing steps.
According to at least one aspect, the method comprises the step of separating the arrangement of the reflective material and the conversion material into a plurality of conversion elements. The arrangement of the reflective material in the conversion material is, for example, separated along cuts transverse to the main direction of extent. For example, the cuts are perpendicular to the main direction of extent. Thus, the conversion elements comprise a top surface and a bottom surface connected by a side face. The side face is formed by the reflective material which covers the side face of the conversion material, which connects a top surface and a bottom surface of the conversion material. Advantageously, the top and bottom surfaces of the conversion material are free of the reflective material, increasing the efficiency of the conversion element.
In at least one aspect, the method for producing a plurality of conversion elements comprises the steps of providing a first mold, having an opening, providing a second mold, and inserting the second mold in the first mold. Further steps are filling a first volume between an inner surface of the first mold and an outer surface of the second mold with a reflective material, removing the second mold, filling a second volume with a conversion material in place of the removed second mold, removing the first mold, and separating the arrangement of the reflective material and the conversion material into a plurality of conversion elements.
The method for producing a plurality of conversion elements described here makes use, inter alia, of the idea that the reflective material surrounds the side faces of the
conversion material, minimizing side emissions.
Currently, the reflective material surrounding the side faces of a conversion material can overflow top and bottom surfaces of a conversion element due to production reasons. The reflective material on the top and bottom surfaces hinders the light extraction as well as the light to be injected in the conversion material.
One idea of the method described here for producing a
plurality of conversion elements is, inter alia, to produce an elongated tube comprising the conversion material in its core, covered by the reflective material on the side face of the conversion material. The tube can be separated into single conversion elements by cutting the tube transverse to the elongation direction. The resulting conversion elements comprise top and bottom surfaces, free of the reflective material. The conversion element can then be applied, for example, to a surface-emitting radiation-emitting
semiconductor chip. Since the reflective material solely surrounds the side faces of a conversion material, this leads, for example, to a reduction of blue light leakage due to side emissions of the semiconductor chip. Moreover, a plurality of conversion elements can be produced while having only one single dispensing process for the reflective
material and the conversion material, respectively.
Advantageously, this may reduce production costs.
According to at least one aspect of the method, a bottom surface of the second mold seals a bottom surface of the opening. For example, a bottom part of the second mold which is not inserted into the opening of the first mold has a cross-sectional area being bigger than the cross-sectional area of the second mold which is inserted in the opening of the first mold. For example, an outer side of the bottom part of the second mold terminates flush with the outer side of the first mold, or is bigger than the outer side of the first mold. For example, the cross-sectional area of the bottom part of the second mold perpendicular to the main direction of extent is equal to the cross-sectional area of the first mold perpendicular to the main direction of extent. In addition, the cross-sectional area of the bottom part of the second mold perpendicular to the main direction of extent may be bigger than the cross-sectional area of the first mold perpendicular to the main direction of extent. Further, the bottom surface, which faces the first mold, of the bottom part of the second mold may be, for example, in direct and immediate contact to the surface of the first or second end part of the first mold.
For example, the direct contact of the bottom surface and the surface of the first or second end part of the first mold is impermeable, for example, to the reflective material. Thus, the bottom surface of the second mold seals the bottom surface of the opening. Within a manufacturing tolerance, for example, the contact is impermeable or substantially
impermeable to the reflective material. Substantially
impermeable means that small quantities of the reflective material could leak out of the contact.
According to at least one aspect, the method comprises the step wherein, before removing the first mold, the conversion material is cured. For example, the reflective material is present in a flowable form to fill the first volume between the inner surface of the first mold and the outer surface of the second mold with the reflective material. Thus, before removing the second mold, the reflective material, for example, is cured by means of annealing or a UV treatment. According to at least one aspect, the method comprises the step wherein, before removing the first mold, the conversion material is cured. For example, the conversion material is present in a flowable form to fill the second volume with the conversion material in place of the removed second mold.
Thus, before removing the first mold, the conversion
material, for example, is cured by means of annealing or a UV treatment .
According to at least one aspect, the method comprises the step wherein, before filling the second volume with the conversion material, a further opening of the first mold is sealed with a cap. The cap comprises, for example, two parts. A bottom part, for example, has a bigger cross-sectional area perpendicular to the main direction of extent than the cross- sectional area of a further opening perpendicular to the main direction of extent. A side face of the bottom part of the cap, for example, terminates flush with the outer side face of the first mold. For example, the cross-sectional area of the bottom part of the cap perpendicular to the main
direction of extent has the same size than the cross- sectional area of the first mold perpendicular to the main direction of extent. It is also possible, for example, that the cross-sectional area of the bottom part of the cap perpendicular to the main direction of extent is bigger than the cross-sectional area of the first mold perpendicular to the main direction of extent. Further, a top surface, which is connected by the side face to a bottom face, of the bottom part of the cap may be, for example, in direct and immediate contact to the surface of the first or second end part of the first mold. For example, the direct contact of the top surface of the bottom part of the cap and the surface of the first or second end part of the first mold is impermeable, for example, to the conversion material. Thus the cap seals the opening at the first or second end part of the first mold. Within a manufacturing tolerance, for example, the contact is
substantially impermeable to the conversion material.
Substantially impermeable means that small quantities of the conversion material could leak out of the contact.
The second part of the cap is, for example, a small elevation on top of the bottom part of the cap. The height of the elevation is, for example, small compared to the size of the arrangement along the main direction of extent. The cross- sectional area of the elevation perpendicular to the main direction of extent is, for example, equal to or smaller than the cross-sectional area of the opening of the first mold perpendicular to the main direction of extent. This
elevation, for example, may be inserted into the opening of the first mold. For example, the elevation ensures that the cap does not get displaced during the following method steps.
According to at least one aspect of the method, at least one of the following components contains or consists of
Polytetrafluoroethylene : the first mold, the second mold, the cap. If the components comprise Polytetrafluoroethylene, at least part of their surfaces are formed of or coated with Polytetrafluoroethylene . For example, the components
containing or consisting of a Polytetrafluoroethylene, PTFE for short, for example Teflon, do not react with materials which are in direct and immediate contact with the
components. For example the components do not react with the reflective material and the conversion material. Thus, for example, the reflective material and the conversion material do not adhere to the components containing or consisting of Polytetrafluoroethylene . Advantageously, the components may be removed easily from the cured reflective material and the cured conversion material. In addition, the components consisting of PTFE exhibit flexible mechanical properties.
For example, the components may be rolled up.
According to at least one aspect, the method comprises the step: before separating the arrangement, the cap is removed. The cap is, for example, detracted from the reflective material, the conversion material and the first mold. Thus, the reflective material, the conversion material and the first mold are free of the cap on a side where the cap was applied .
According to at least one aspect of the method, the
conversion elements are separated by sawing. The conversion elements are separated, for example, by means of sawing, using a sawing blade, wire or chain, for example. Thus, the so produced conversion elements have a roughening on the top surface and the bottom surface of the conversion element. Advantageously, the roughening reduces the probability of total reflection by the conversion material.
In addition, a conversion element is provided. Preferably, the conversion element can be produced by the method for producing a plurality of conversion elements described herein before. Thus, a conversion element described here may be produced by the method described here or is produced by the described method. All features disclosed in connection with the method for producing a plurality of conversion elements are therefore also disclosed in connection with the
conversion element and vice versa.
According to at least one aspect, the conversion element comprises a conversion material. For example, the conversion material converts electromagnetic radiation into
electromagnetic radiation of another wavelength range. The conversion material has a main extension plane parallel to a top surface and a bottom surface of the conversion material.
A side surface of the conversion material, for example, connects the top surface and the bottom surface.
According to at least one aspect, the conversion element comprises a reflective material. The reflective material, for example, is formed to be reflective for the electromagnetic radiation and the converted electromagnetic radiation. For example the reflective material covers the side face of the conversion material completely. Further, the reflective material is in direct and immediate contact to the side face of the conversion material. A top surface and a bottom surface of the reflective material terminate flush with the top surface and the bottom surface of the conversion
material. The top surface and the bottom surface of the conversion material are free of a reflective material. Within a manufacturing tolerance, for example, the top surface and the bottom surface of the conversion material are
substantially free of the reflective material. Substantially free means that small quantities of the reflective material could be present on the top surface and the bottom surface of the conversion material.
According to at least one aspect of the convers on element a top surface and a bottom surface of the conversion element comprise traces of a separation step. The conversion elements are, for example, separated along cuts parallel to the main extension plane. Since the conversion elements are separated, for example, by means of sawing, creating the top and bottom surfaces of the conversion elements, the top and the bottom surfaces comprise traces of the sawing process like, for example, sawing marks. This means that the top and bottom surfaces of the conversion material and the reflective material comprise the traces of the separation step.
According to at least one aspect, the reflective material comprises a matrix material and radiation-reflective
particles. The reflective material comprises, for example, the matrix material in which the radiation-reflective
particles are introduced. The matrix material may be, for example, a resin such as an epoxy or a silicone, or a mixture of these materials. The radiation-reflective particles are, for example, titanium oxide particles. Thus the reflective material, for example, has a reflectivity of at least 90% for electromagnetic radiation in the visible range. For instance, the reflective material is white.
According to at least one aspect, the conversion material is formed to convert electromagnetic radiation of a first wavelength range into electromagnetic radiation of a second wavelength range. That is, the conversion element is of wavelength-converting configuration. The term "wavelength conversion" is, for example, a conversion of electromagnetic radiation of the first wavelength range into electromagnetic radiation of the second wavelength range, for example being a longer wave. For example, during wavelength conversion electromagnetic radiation of the first wavelength range is absorbed by a wavelength-converting element, converted by electronic processes at an atomic and/or molecular level into electromagnetic radiation of the second wavelength range and reemitted. For example, the term "wavelength conversion" does not mean mere scattering or merely absorption of
electromagnetic radiation.
According to at least one aspect, the conversion material comprises a matrix material and luminescence conversion particles. The matrix material, for example, is a resin such as an epoxy or a silicone, or a mixture of these materials. The luminescence conversion particles impart the wavelength converting properties to the conversion material and thus to the conversion element. For example, one of the following materials is suitable for the luminescence conversion
particles: rare-earth-doped garnets, rare-earth-doped
alkaline earth sulfides, rare-earth-doped thiogallates , rare- earth-doped silicates, rare-earth-doped orthosilicates, rare- earth-doped chlorosilicates , rare-earth-doped alkaline-earth- silicon nitrides, rare-earth-doped oxynitrides, rare-earth- doped aluminum oxynitrides, rare-earth-doped silicon
nitrides, rare-earth-doped sialons, quantum dots. These materials may also be used without a matrix material and may be applied directly. The conversion element, for example, consists of one of these materials.
According to at least one aspect, the matrix material of the reflective material and the matrix material of the conversion material consist of or contain the same materials. This means that the matrix materials, for example, are a resin such as an epoxy or a silicone, or a mixture of these materials.
Thus, the two matrix materials may have, for example, the same thermal expansion coefficient. According to at least one aspect, traces of a separation step are in the form of a roughening of the top surface and the bottom surface of the conversion element. Since the
separation step is achieved, for example, by means of sawing, using a sawing blade, the top surface and the bottom surface of the conversion element are roughened, leading to a
roughening of the top and bottom surfaces of the conversion element, for example. Advantageously, the roughening reduces the probability of total reflection at the top surface and the bottom surface of the conversion element.
In addition, an optoelectronic component is provided.
Preferably, the optoelectronic component may comprise a conversion element, which can be produced by the method for producing a plurality of conversion elements described herein before. All features disclosed in connection with the method for producing a plurality of conversion elements and the conversion element are therefore also disclosed in connection with the optoelectronic component and vice versa.
According to at least one aspect, the optoelectronic
component comprises a semiconductor chip. For example, the semiconductor chip comprises a semiconductor body. The semiconductor body is, for example, a semiconductor body grown epitaxially. The semiconductor body comprises an n- conducting region, an active region provided for generating electromagnetic radiation, and a p-conducting region.
In the active region of the semiconductor body, primary electromagnetic radiation in the spectral range between UV radiation and infrared radiation, in particular in the spectral range of visible light, is generated for example during operation. For this purpose, the semiconductor body is based for example on a III-V semiconductor material, for example on a nitride compound semiconductor material.
According to at least one aspect, the optoelectronic
component comprises a here described conversion element. The conversion element is formed to convert the primary
electromagnetic radiation, produced by the semiconductor chip during operation, into, for example, longer-wavelength secondary radiation.
According to at least one aspect, the conversion element is placed on an emission surface of the semiconductor chip. For example, the conversion element is glued to the semiconductor chip or the conversion element is fixed to a housing of the semiconductor chip. The primary electromagnetic radiation generated during operation of the semiconductor chip leaves the semiconductor body, for example, at least partly via the emission surface of the semiconductor chip, being for example a top or bottom surface of the semiconductor chip. For example, the conversion element is placed on the top or bottom surface of the semiconductor chip; thus, the primary electromagnetic radiation may be converted by means of the conversion element.
A cross-sectional area perpendicular to the main direction of extent of the emission surface of the semiconductor chip may be, for example, bigger or equal in size compared to the cross-sectional area perpendicular to the main direction of extent of the conversion material.
If a surface-emitting semiconductor chip is used, the primary electromagnetic radiation emitted during operation leaves the top or bottom surface of the semiconductor chip. This primary electromagnetic radiation is converted into secondary radiation. The reflective layer of the conversion element, for example, leads to a reflection of the primary and
secondary electromagnetic radiations, which leave the top or bottom surface of the semiconductor chip in a transverse direction. The primary electromagnetic radiation is reflected again and enters the conversion material again. Thus, the remaining primary electromagnetic radiation is converted again. Furthermore, the primary and secondary radiations are directed by means of the reflective layer, for example, in the direction of a light-emitting surface of the
optoelectronic component. This advantageously increases the light extraction.
In the following, the method for producing a plurality of conversion elements as well as a conversion element described herein will be discussed in more detail on the basis of exemplary embodiments and the associated figures.
The figures show:
Figures 1A, IB, 2, 3, 4, 5A, 5B, 6 and 7 schematic
representations of process steps of an embodiment of a method described herein for producing a plurality of conversion elements ,
Figures 8A and 8B schematic representations of an embodiment of a conversion element described herein,
Figures 9A and 9B schematic representations of exemplary embodiments of an optoelectronic component. Identical, similar or identically acting elements are
provided with the same reference signs in the figures. The figures and the size ratios of the elements illustrated in the figures relative to one another are not to be regarded as being drawn to scale. Rather, individual elements may be exaggerated in size for better representation and/or better intelligibility.
With reference to Figures 1A, IB, 2, 3, 4, 5A, 5B, 6 and 7, an exemplary embodiment of a method for the production of a plurality of conversion elements 1 described herein is shown.
As becomes apparent from Figure 1A, a first mold 2 is
provided. The first mold 2 is of the form of a tube, having an opening 22. The opening 22 penetrates the first mold 2 completely. The opening 22 defines a first inner volume.
Here, the first mold 2 contains or consists of PTFE.
As shown in Figure IB, a second mold 3 is provided. The second mold 3 is of the form of a pillar, having a bottom part 33 and a top part 34. The cross-sectional area of the bottom part 33 of the second mold 3 perpendicular to a main direction of extent is bigger than the cross-sectional area of the top part 34 of the second mold 3. Further the cross- sectional area of the top part 34 of the second mold 3 perpendicular to the main direction of extent is smaller than a cross-sectional area of the first mold 2 perpendicular to the main direction of extent. Here, a first end part of the second mold 3b and a second end part of the second mold 3c face each other.
The second mold 3 may be larger than the first mold 2 along the main direction of extent. The top part 34 of the second mold 3, which has the same length as the first mold 2, defines a second inner volume. The length of the first mold 2 is the distance between a first end part 2b and a second end part 2c of the first mold 2. Here, the second mold 3 contains or consists of PTFE.
The second mold 3 is inserted in the first mold 2, as shown in Figure 2. The first mold 2 penetrates the opening 22 completely. Thus a first volume 2d is produced, being the volume between an inner surface of the first mold 2a and an outer surface of the second mold 3a over the length of the first mold 2. In other words, the first volume 2d is the first inner volume minus the second inner volume. The inner surface of the first mold 2a and the outer surface of the second mold 3a have a constant distance parallel to the main direction of extent.
Here, an outer surface of the bottom part 33 of the second mold 3 terminates flush with an outer surface of the first mold 2. The cross-sectional area of the bottom part of the second mold 33 is equal to the cross-sectional area of the first mold. Further, a top surface of the bottom part of the second mold 33 is in direct and immediate contact to a surface of the second end part 2c of the first mold 2.
According to Figure 3, the first inner volume is filled with a reflective material 4. The reflective material 4 terminates flush with the first and the second end parts 2b and 2c of the first mold.
As shown in Figure 4, the second mold 3 is removed. Thus, removing the second mold 3 reveals a further opening 23, defining the second inner volume. The second mold 3 contains or consists of PTFE, which does not react with the reflective material 4 while being in direct and immediate contact with the second mold 3. Thus, the reflective material 4 does not adhere to the second mold 3 and the second mold 3 can be removed easily.
As becomes apparent from Figure 5A, a cap 5 is provided. The cap 5 comprises two parts. A bottom part 55 and a top part 56. The bottom part of the cap 55 has a bigger cross- sectional area than the cross-sectional area of the further opening 23 of the first mold 2. Here, the cross-sectional area of the bottom part of the cap 55 has the same size than the cross-sectional area of the first mold 2.
The top part of the cap 56 is a small elevation on top of the bottom part of the cap 55. The cross-sectional area of the top part of the cap 56 is smaller than the cross-sectional area of the further opening 23 of the first mold 2.
According to Figure 5B, the cap is arranged on the second end part of the first mold 2c. Here, the top part of the cap 56 is inserted into the further opening 23 of the first mold 2 and ensures that the cap 5 does not get displaced during the following processing step.
A top surface 5a of the bottom part 55 of the cap is in direct contact with a surface of the second end part of the first mold 2c. Thus the further opening 23 of the first mold on the second end part 2c is sealed with the cap 5.
As shown in Figure 6, a conversion material 6 is filled in the second volume 3d in place of the removed second mold 3. The second volume 3d is here the first inner volume minus the first volume 2d. The conversion material 6 fills the further opening 23 completely. Thus, the conversion material 6 fills the further opening 23 such that the top surface 6a and the bottom surface of the conversion material 6 terminate flush with the first and the second end parts 2b and 2c of the first mold 2.
According to Figure 7, the first mold 2 is removed. The first mold 2 contains or consists of PTFE, which does not react with the reflective material 4 while being in direct and immediate contact with the first mold 2. Thus, the reflective material 4 does not adhere to the first mold 2 and the first mold 2 can be removed easily.
The reflective material 4 is free of the first mold 2 after removing. The reflective material 4 covers a circumferential surface of the conversion material 6. The reflective material 4 then protects the conversion material 6 from chemical damage. The reflective material 4 also protects the
conversion material 6 against mechanical damage during further processing steps.
The so produced arrangement comprising the conversion
material 6 and the reflective material 4 is separated by cuts 7 through the arrangement transverse to the main direction of extent, indicated by a dashed line in Figure 7. The
conversion elements 1 are separated, for example, by means of sawing, using a sawing blade, for example.
With reference to Figures 8A and 8B, exemplary embodiments of conversion elements 1 are shown. As becomes apparent from Figure 8A, a conversion element 1 comprises a conversion material 6 and a reflective material 4. The reflective material 4 surrounds the conversion
material 6 completely at its side face. Further, the
reflective material 4 is in direct and immediate contact to the side face of the conversion material 6.
A top surface and a bottom surface of the conversion material 6 terminate flush with a top surface and a bottom surface of the reflective material 4. Further, the top and bottom surfaces of the conversion material 6 are free of the
reflective material 4.
The conversion element 1 has a main extension plane parallel to the top and bottom surfaces of the conversion material 6 and the reflective material 4. Here, the form of the
conversion element 1 in the main extension plane is a circle, and also the conversion material 6 and the reflective
material 4 are of circular form.
Moreover, a top surface la and a bottom surface lb of the conversion element 1 show traces of a separation step 8, for example a roughening due to the separation step.
According to Figure 8B, a further embodiment of the
conversion element 1 is shown. The features of the embodiment according to Figure 8A can be applied to the embodiment of the conversion element according to Figure 8B. A difference to the embodiment according to Figure 8A is that the form of the conversion element 1 in the main extension plane is a rectangle and also the conversion material 6 and the
reflective material 4 are of rectangular form. With reference to Figures 9A and 9B, exemplary embodiments of a here described optoelectronic component are shown.
As shown in Figures 9A and 9B, the optoelectronic component 10 comprises a conversion element 1 and a semiconductor chip 9. Here, the conversion element 1 is placed on an emission surface of the semiconductor chip 9. The conversion elements 1 have, for example, the same features as described in
Figures 8A and 8B, respectively.
Here, a cross-sectional area perpendicular to the main direction of extent of the emission surface of the
semiconductor chip 9 is equal in size compared to the cross- sectional area perpendicular to the main direction of extent of the conversion material 6.
The description made with reference to exemplary embodiments does not restrict the invention to these embodiments. Rather, the invention encompasses any novel feature and any
combination of features, including in particular any
combination of features in the claims, even if this feature or this combination is not itself explicitly indicated in the claims or exemplary embodiments.
List of references
1 conversion element
la top surface conversion element lb bottom surface conversion element
10 optoelectronic component
2 first mold
2a inner surface first mold
2b first end part first mold
2c second end part first mold
2d first volume
22 opening
23 further opening
3 second mold
3a outer surface second mold
3b first end part second mold
3c second end part second mold
3d second volume
33 bottom part second mold
34 top part second mold
4 reflective material
5 cap
5a top surface cap
55 bottom part cap
56 top part cap
6 conversion material
6a top surface conversion material
7 separation cut
8 traces separation step
9 semiconductor chip

Claims

Claims
1. Method for producing a plurality of conversion elements (1) comprising the steps of
providing a first mold (2), having an opening (22), providing a second mold (3) ,
inserting the second mold (3) in the first mold (2), filling a first volume (2d) between an inner surface of the first mold (2a) and an outer surface of the second mold (3a) with a reflective material (4),
removing the second mold (3) ,
filling a second volume (3d) with a conversion material (6) in place of the removed second mold (3),
removing the first mold (2),
separating the arrangement of the reflective material (4) and the conversion material (6) into a plurality of conversion elements (1) .
2. Method according to the preceding claim,
wherein a bottom surface of the second mold (3) seals a bottom surface of the opening (22) .
3. Method according to one of the preceding claims, wherein, before removing the second mold (3) , the reflective material (4) is cured.
4. Method according to one of the preceding claims, wherein, before removing the first mold (2), the conversion material (6) is cured.
5. Method according to one of the preceding claims, wherein, before filling the second volume (3d) with the conversion material (6), a further opening (23) of the first mold is sealed with a cap (5) .
6. Method according to the preceding claim,
wherein at least one of the following components contains or consists of Polytetrafluoroethylene : the first mold (2), the second mold (3) , the cap (5) .
7. Method according to one of the two preceding claims, wherein, before separating the arrangement, the cap (5) is removed .
8. Method according to one of the preceding claims,
wherein the conversion elements (1) are separated by sawing.
9. Conversion element (1) comprising
a conversion material (6), and
a reflective material (4), wherein
a top surface (la) and a bottom surface (lb) of the conversion element (1) comprise traces of a separation step
10. Conversion element (1) according to the preceding claim, in which the reflective material (4) comprises a matrix material and radiation-reflective particles.
11. Conversion element (1) according to one of the preceding claims 9 to 10,
in which the conversion material (6) is formed to convert electromagnetic radiation of a first wavelength range into electromagnetic radiation of a second wavelength range.
12. Conversion element (1) according to one of the preceding claims 9 to 11,
in which the conversion material (6) comprises a matrix material and luminescence conversion particles.
13. Conversion element (1) according to one of the preceding claims 9 to 12,
in which the matrix material of the reflective material (4) and the matrix material of the conversion material (6) consist of or contain the same materials.
14. Conversion element (1) according to one of the preceding claims 9 to 13,
in which traces of a separation step (8) are in form of a roughening of the top surface (la) and the bottom surface (lb) of the conversion element (1) .
15. Optoelectronic component (10) comprising
a semiconductor chip (9), and
the conversion element (1) according to one of the preceding claims 9 to 14, wherein
the conversion element (1) is placed on an emission surface of the semiconductor chip.
PCT/EP2018/051334 2018-01-19 2018-01-19 Method for producing a plurality of conversion elements, conversion element and optoelectronic component WO2019141374A1 (en)

Priority Applications (1)

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PCT/EP2018/051334 WO2019141374A1 (en) 2018-01-19 2018-01-19 Method for producing a plurality of conversion elements, conversion element and optoelectronic component

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PCT/EP2018/051334 WO2019141374A1 (en) 2018-01-19 2018-01-19 Method for producing a plurality of conversion elements, conversion element and optoelectronic component

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150048392A1 (en) * 2012-03-06 2015-02-19 OSRAM Opto Semicondusctors GmbH Wavelength conversion element, light-emitting semiconductor device and display apparatus therewith, and method for producing a wavelength conversion element
US20150136306A1 (en) * 2013-11-18 2015-05-21 Nichia Corporation Method for manufacturing light distribution member, and method for manufacturing light emitting device
US20160155912A1 (en) * 2013-07-30 2016-06-02 Osram Opto Semiconductors Gmbh Method of producing a cover element and an optoelectronic component, cover element and optoelectronic component
EP3093893A1 (en) * 2015-05-15 2016-11-16 Nichia Corporation Method for manufacturing light distribution members, method for manufacturing light emitting device, light distribution member, and light emitting devices
US20170250318A1 (en) * 2016-02-25 2017-08-31 Samsung Electronics Co., Ltd. Method of manufacturing light emitting device package
US20180006167A1 (en) * 2016-07-04 2018-01-04 Koito Manufacturing Co., Ltd. Sintered compact and light emitting device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150048392A1 (en) * 2012-03-06 2015-02-19 OSRAM Opto Semicondusctors GmbH Wavelength conversion element, light-emitting semiconductor device and display apparatus therewith, and method for producing a wavelength conversion element
US20160155912A1 (en) * 2013-07-30 2016-06-02 Osram Opto Semiconductors Gmbh Method of producing a cover element and an optoelectronic component, cover element and optoelectronic component
US20150136306A1 (en) * 2013-11-18 2015-05-21 Nichia Corporation Method for manufacturing light distribution member, and method for manufacturing light emitting device
EP3093893A1 (en) * 2015-05-15 2016-11-16 Nichia Corporation Method for manufacturing light distribution members, method for manufacturing light emitting device, light distribution member, and light emitting devices
US20170250318A1 (en) * 2016-02-25 2017-08-31 Samsung Electronics Co., Ltd. Method of manufacturing light emitting device package
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