DE102011107892A1 - Method for coating e.g. chip-on-board UV-LED module utilized in solar cell, involves curing and cross-linking liquid silicone with optoelectronic components and carriers, and removing carrier with hardened silicone coating from mold - Google Patents

Abstract

The method involves pouring a liquid silicone in an upwardly opened mold, which exhibits an external dimension exceeding corresponding to outer dimensions of carriers (2, 2'). The carriers are inserted into the mold such that optoelectronic components i.e. LEDs (4, 4'), are completely immersed into the silicone. The carriers are partially dipped over an entire surface in the silicone. The silicone is cured and cross-linked with the optoelectronic components and the carriers. The carriers are removed with a hardened silicone coating from the mold. An independent claim is also included for an optoelectronic chip on board module.

Description

The invention relates to a method for coating an optoelectronic chip-on-board module, which comprises a flat carrier, which is equipped with one or more optoelectronic components, with a transparent, UV and temperature-resistant coating of a silicone, a corresponding optoelectronic chip On-board module and a system with several optoelectronic chip-on-board modules.

Generic optoelectronic chip-on-board modules are used, for example, as luminous bodies, as high-power UV LED lamps, as photovoltaic modules, sensors or the like. In the context of the invention, the optoelectronic components used in this case are, for example, but not exclusively, LEDs or photodiodes in the form of chips or other components which, in the chip-on-board module, are mounted on a flat carrier, ie a metal, Ceramic or silicon substrate, a metal core or FR4 circuit board, a glass substrate, a plastic support o. Ä. Are arranged. These chip-on-board modules must be protected against mechanical damage and corrosion. For this purpose, the most compact and lightweight solutions are sought.

Light-emitting diode modules with a light-emitting diode array and a microlens array in various configurations are known from the prior art. Examples of such light-emitting diode modules and methods for their production are exemplary in US 7,638,808 B2 , in US 20100065983 A1 , in US 20070045761 A1 or in US 7,819,550 B2 described. Also in the post-published German patent application with the number DE 10 2010 044 470 A method for producing a microlens array for an optoelectronic module is described.

Protection in the form of packages on chip-on-board modules is often costly and technologically complex. A practical alternative to the protection of chip-on-board modules is a surface encapsulation of the components with a plastic-based potting material. Together with other functional components, such as interconnects and bonding elements, the optoelectronic components in chip-on-board modules together protected with a flat carrier by coatings from mechanical damage and corrosion.

Usually this injection molding or casting process with epoxy resins are used. These are first applied liquid as potting material and then cured thermally and / or radiation-induced. Since the potting material is initially liquid, a flow of the potting compound must be avoided. This is usually done by a form or a fixed frame.

An alternative for this is the so-called "dam-and-fill" method, wherein first a plastic dam is applied to the carrier of the chip-on-board module, which encloses a surface of the carrier, in which subsequently a liquid filling compound of epoxy resin is filled. This is cured. Dam and filling compound together form the coating of the module. To produce the dam, a viscous polymer is applied or drawn with a dispensing device in this method and then cured, so that potting material can be poured onto the area enclosed by the dam without this flowing away.

However, the plastic dam created in this way is not transparent. Therefore, such coated optoelectronic chip-on-board modules, ie chip-on-board modules, which are equipped with optoelectronic components, such as LEDs or photodiodes, impaired towards the edge in their light radiation intensity or their photosensitivity.

These mentioned methods using epoxy resins are less suitable for optoelectronic application because epoxy resins are not UV and temperature resistant. They are therefore not stable, for example, in a high-power UV-LED module or in intense sunlight with UV components, as they occur in photovoltaics. They age rapidly under UV exposure and are destroyed.

Other solutions, such as the gluing of a glass frame or a glass pan, which are transparent, UV and temperature stable, require a very complex installation of the frame and a difficult to manufacture compactness of the frame. Moreover, such a solution is associated with a higher weight than a potting solution. For rigid glass materials, a most necessary adjustment of the thermal expansion coefficients of the composite materials also represents another hurdle, especially when the later products are exposed to thermal cycles.

In a combination solution of a glass frame and a casting with a suitable non-epoxy-based material, such. As a temperature and UV-stable silicone smallest gaps between the frame and substrate can cause the highly creepable silicone could leak during casting. In addition, space must be provided for the frame on the substrate. This impairs the best possible utilization of the substrate surface and / or a desired alignability.

Known injection molding and casting methods require a vacuum seal sealing the edge of the module due to the need to prevent flow of the liquid casting material. This leads to a loss of usable area on the module, since the edge region of components must be kept free.

So far, no method for the realization of a surface coating for chip-on-board modules is known in which materials are used both in the surface and in the edge region of the encapsulation, which are both UV-stable and temperature-stable and beyond for electromagnetic radiation from the ultraviolet to the infrared spectral range are transparent.

In EP 1 657 758 A2 a corresponding casting method for LED units on a support structure for the production of lenses for the LED units is known in which liquid silicone is filled into a negative mold for the lens structure and the support structure are placed with the LEDs on the mold, so that the LEDs are immersed in the liquid lens material. Mounted around the support structure of the module and mold is a vacuum seal which engages the edge of the support structure or substrate of the module and the mold and presses the two together under high pressure to prevent the liquid material from escaping. In this way, lenses are molded around the LEDs while the area between the LEDs remains substantially unwetted by the casting material, except for entraining material.

With this method it is not possible to provide optoelectronic chip-on-board modules with a coating which is transparent, UV and temperature-resistant and which can be equipped with optoelectronic components, in particular under full area utilization.

For the use of chip-on-board technology for the production of high-performance UV-LED modules that radiate surface, or of photodiode arrays, a surface casting, which avoids the disadvantages mentioned, is more advantageous. For reasons of optical efficiency and the best possible modularity of modules, the encapsulation should be transparent both in the area and in the edge area. Likewise, high temperature and UV stability are relevant both for the production of corresponding optoelectronic components and for long-term stable functionality.

Compared to this prior art, the present invention is therefore based on the object of providing a method for producing an optoelectronic chip-on-board module and a corresponding optoelectronic chip-on-board module, in which a transparent, UV and temperature-resistant coating over the entire surface on the support is possible and the full support surface for the arrangement of optoelectronic components is available.

• a) Vergießen eines flüssigen Silikons in eine nach oben offene Form, die Außenmaße aufweist, die den Außenmaßen des Trägers entsprechen oder diese übersteigen,
• b) Einführen des Trägers in die Form, wobei die optoelektronische Komponente oder die optoelektronischen Komponenten vollständig in das Silikon eingetaucht werden und eine Oberfläche des Trägers das Silikon vollflächig berührt oder der Träger wenigstens teilweise vollflächig in das Silikon eintaucht,
• c) Aushärten und Vernetzen des Silikons mit den optoelektronischen Komponenten und dem Träger, und
• d) Entnehmen des Trägers mit der Beschichtung aus dem ausgehärteten Silikon aus der Form.

This object is achieved by a method for coating an optoelectronic chip-on-board module, which comprises a flat carrier, which is equipped with one or more optoelectronic components, with a transparent, UV and temperature-resistant coating of a silicone, which comprising the following process steps:

• a) pouring a liquid silicone in an upwardly open mold having external dimensions corresponding to or exceeding the external dimensions of the carrier,
• b) inserting the carrier into the mold, wherein the optoelectronic component or the optoelectronic components are completely immersed in the silicone and a surface of the carrier touches the silicone over the entire surface or the carrier is at least partially immersed in its entirety in the silicone,
• c) curing and curing the silicone with the optoelectronic components and the carrier, and
• d) removing the carrier with the coating of the cured silicone from the mold.

In contrast to the prior art according to EP 1 657 758 A2 For example, the coating applied as a result of the process to the optoelectronic chip-on-board module is present to the edge and possibly beyond the edge of the support in a thickness sufficient for corrosion protection and mechanical protection. This coating is transparent to the entire coated surface of the support, UV and temperature resistant. Since the coating extends to the edge of the carrier and beyond, it is possible to arrange the optoelectronic components as desired on the carrier. Because there is no need for a vacuum seal that is circumferentially mounted around the carrier and corresponding mold, and therefore there is no edge to be left free from opto-electronic components, optimum area utilization is possible.

In the method according to the invention, the creep properties of the silicone are utilized since they ensure efficient wetting and thus efficient protection of the support of the optoelectronic components and other structures and components arranged thereon. In the method according to the invention is liquid silicone cast into the mold, in which then the carrier is inserted upside down. The filling level of the silicone is chosen such that the carrier touches with its surface just the surface of the silicone or immersed in it. The liquid silicone is then thermally crosslinked together with the mold and the substrate, for example. Alternatively or additionally, radiation crosslinking may also take place. When the silicone is fully cured, the substrate, including the now cured, adherent and transparent encapsulant, is removed from the mold. This results in a UV and temperature-stable protection of chip-on-board modules up to intensities of a few 10 W / cm ² or even some 100 W / cm ² and about 200 ° C. This protection is transparent and uniform over the entire area and edge area and also provides mechanical protection of the beam and superstructures.

Preferably, the process steps a) and / or b) and / or c) and / or d) are carried out under an elevated atmospheric pressure, in particular at an atmospheric pressure between 4 and 10 bar, in particular between 5 and 7 bar. The increased atmospheric pressure, which is not a mechanical pressure of the carrier against the mold, causes gas bubbles in the silicone mass to be reduced until they completely close and the gas diffuses outward through the silicone mass.

In addition, it is preferably provided to expose the silicone to a vacuum, for example at about 10 mbar, before filling in, in order to allow the gas inclusions to outgas. Thus, a gas-free silicone material is obtained, which can then be filled into the mold.

If optically functional materials, in particular phosphorescent and / or scattering materials or particles, are or are preferably mixed into the liquid silicone, the optical properties of the chip-on-board optoelectronic modules can be further modified. Thus, by means of phosphorescent materials, a wavelength shift and a color change of the emitted light can be realized, while scattering materials or particles cause a homogenization of the emitted light.

Preferably, a surface structure predetermined by the mold or later added is produced on a surface of the coating. These are, for example, elevations or recesses which are shaped inversely from the mold, for example, on the surface of the encapsulation of the finished module. In this way, macroscopic and microscopic primary optics or general surface structures, such as, for example, lenses, in particular microlenses, or light-scattering roughenings, can be applied directly to the module.

Advantageously, the carrier is or is equipped up to one or more edges with optoelectronic components. In this way, the existing support surface is optimally utilized. This also has the advantage that system of several chip-on-board modules, which are arranged side by side, across the boundaries between the carriers across a large area allow a uniform arrangement of the optoelectronic components. The at least one optoelectronic component can have, for example, one or more photodiodes and / or one or more light-emitting diodes (LEDs). In particular, the carrier can be equipped with optoelectronic components such that a photodiode array and / or a light-emitting diode array is produced.

Advantageously, the carrier is borderless and / or coated over the edge. In this way, in a rimless coating the full design freedom is maintained, while a coating that goes over the edge and thus encloses the side surfaces of the wearer in whole or in part, additionally prevents interference from the side or dirt in the gap between the coating and penetrate the surface of the carrier.

The inventive method and its developments thus offer not only the advantage that a full-surface UV and temperature-stable transparent coating of the carrier is possible, and the further advantages that the design freedom of the arrangement of the optoelectronic components is maximized on the support and due to the transparent edge of the Possibilities for seamless stackability of chip-on-board modules to each other is improved.

The method can be used to set optical functionalities targeted, by means of surface shaping and by the incorporation of optically functional materials in the potting material. The hardness of the silicone can be chosen to dampen thermally induced stresses caused by different coefficients of expansion between carriers, chip-on-board devices, and interconnect materials. Typical Shore hardnesses are between the hardness of a gel and a Shore hardness near 100.

The method can be carried out in particular in such a way that the silicone is shaped such that at least one optical component, in particular at least one lens and / or at least one lens array, for example at least one microlens and / or at least one microlens array, is formed in the silicone. This can be done, for example, by impressing a corresponding shape on the silicone during and / or after curing and crosslinking, for example in the form of a surface structure which gives the surface of the silicone the corresponding effect of the at least one optical component ,

Furthermore, it is also possible to achieve attenuation of thermally induced voltages in the optoelectronic module or parts thereof by suitable structuring of the mold. Such thermally induced stresses can occur in particular during a curing process or due to temperature changes as a result of the operation of the module, for example of the array. For attenuation of these thermally induced voltages, for example, a targeted structuring of the mold, which is also referred to as a casting mold can be used, for example, by partially thin Silkonschichten between optically active thicker silicone layers. The latter possibility, for example, similar to the known expansion joint principle in road construction.

The method can furthermore be carried out such that the chip-on-board module has at least one primary optic adjacent to the at least one optoelectronic component and optionally at least one secondary optic, wherein at least one optic selected from the group consisting of the primary optics and the secondary optics the silicone is formed.

In the context of the present invention, optics is generally understood to mean an element which has a collecting and / or collimating and / or scattering effect on a light bundle. The optics, in particular the primary optics and / or the secondary optics, may for example comprise at least one optical element selected from the group consisting of a lens, a reflector, a diffuser, an optical grating, a hologram. Combinations of said and / or other optical elements are conceivable.

For example, an optical system may have at least one converging lens and / or at least one diffusing lens and / or at least one reflector, for example a mirror, with a collecting or scattering effect and / or at least one diffuser. Combinations of the mentioned effects and / or structures are also conceivable. Thus, for example, a converging lens may have a rough surface, so that the light collimates, but scatters the light on smaller local areas and thus mixes it, for example. For larger lens structures, which may be arranged, for example, over a plurality of optical components and may comprise, for example, a plurality of LEDs, segmental compositions of local scattering and collecting regions are also conceivable.

For example, a collecting optic can also be wholly or partially configured as a convex optic. For example, a scattering optic can be wholly or partially configured as a concave optic. For example, a converging lens may be a convex lens, and a dispersing lens may be a concave lens.

Furthermore, as an alternative or in addition, a function of a diffuser may also be provided. For this purpose, for example, one or more regular or irregular structures can be provided, in particular in a small space with dimensions, for example in the sub-millimeter range and typically in the range of micrometers, in which, for example, rapid variations between concave and convex shape are realized, in particular in the form of a rough profile.

Again alternatively or in addition to one, several or all of the already mentioned optical elements, the optics, in particular the primary optics and / or the secondary optics, can furthermore also comprise other types of diffractive structures. In particular, for optoelectronic components in the form of diode lasers, but also for other types of optoelectronic components, the optics, in particular the primary optics and / or the secondary optics, could also comprise one or more diffractive optical elements, which may have light-diffractive effects, such as amplitude and or phase grating structures, which may be structured, for example, on the scale of the wavelength of the light, such as gratings in transmission or reflection, phase grating in transmission or reflection, volume holograms or combinations of said and / or other diffractive optical elements. Such diffractive optical elements as optical elements of primary optics and / or secondary optics can be used, for example, for optoelectronic components in the form of narrow-band, monochromatic light sources.

If the optics, in particular the primary optics and / or the secondary optics, comprises at least one reflector, then the reflector can be configured in various ways. Thus, in particular different profiles of the reflector, so reflector geometries and / or reflector profiles can be used. For example, a reflector, in particular in a sectional plane parallel to an optical axis of the reflector, at least partially have at least one profile selected from the group consisting of: a straight profile, a parabolic profile, an elliptical profile, a profile of a conic section, a free-form profile, a trapezoidal shape profile.

Accordingly, a primary optic is to be understood as an optic which directly adjoins the at least one optoelectronic component, so that light emerging from the optoelectronic component enters the primary optic directly or so that light entering the optical component immediately before entering the optoelectronic component Component passes the primary optic. For example, the primary optics may comprise one or more lenses, in particular microlenses, which are formed, for example, in the silicone and / or a coating comprising the silicone and which are placed directly on the at least one optoelectronic component or in which the optoelectronic component is completely or partially embedded , Alternatively or additionally, the primary optics may have one or more reflectors, at which the light emerging from the optoelectronic component is reflected and thereby focused or scattered, or at which the light entering or entering the optoelectronic component is bundled or scattered, or otherwise deflected.

The term primary optics thus characterizes at least one beam-shaping element which is adjacent to a light path of the optoelectronic component without further optical components being arranged between the primary optics and the optoelectronic component, the term primary optics being used independently of whether further optics, especially a secondary optic, are present or not.

Accordingly, a secondary optic is to be understood as an optic which is arranged in the optoelectronic chip-on-board module such that the light must pass through at least one further optic on a light path between the secondary optics and the at least one optoelectronic component. Thus, for example, light emerging from the optoelectronic component can first pass through a primary optic before the light passes through a secondary optic. Alternatively, light entering the optoelectronic component can first pass through the secondary optics, then the primary optics, before the light finally enters the optoelectronic component.

The at least one optional primary optics can have, for example, at least one lens, in particular a plurality of lenses, in particular microlenses. For example, the optoelectronic chip on-board module may have a plurality. Optoelectronic components which are arranged in a matrix and / or an array, for example a light-emitting diode array and / or a photodiode array. A plurality of elements of a primary optics may be assigned to this plurality of optoelectronic components, for example such that exactly one component of the primary optics and / or one defined group of components is assigned to the primary optics in each case of an optoelectronic component or a group of optoelectronic components. For example, exactly one lens may be seated on each optoelectronic component, or it may be seated on a group of optoelectronic components, a common lens for this group.

The at least one optional secondary optics may, for example, have at least one reflector and / or at least one lens. For example, in turn, an assignment of elements of the secondary optics to optoelectronic components can be carried out, for example, in turn, in which each element or groups of elements of an array of the optoelectronic components are each assigned one or more elements of the secondary optics. For example, the secondary optics may comprise a plurality of reflectors, for example a plurality of concave mirrors, which may be arranged, for example, in a matrix and / or an array. Each concave mirror may for example be associated with an optoelectronic component and / or a group of optoelectronic components, for example in that the optoelectronic component is arranged wholly or partially within the concave mirror.

The method can generally also be carried out such that the primary optics and the secondary optics are wholly or partly made of different materials, for example different silicones of the type described. In particular, the primary optics and the secondary optics can be wholly or partly made of materials, for example by means of successive ones Potting methods of the type described, which have different refractive indices. For example, the primary optics can be made wholly or partly using a silicone having a first refractive index n1, and the secondary optics wholly or partly using a silicone having a second refractive index n2.

For example, an optoelectronic chip-on-board module can be produced in this way, which has a primary optics, for example a primary optic lens array, with material n1, and a secondary optics, which For example, a combination of at least one reflector and at least one silicone lens may have, wherein, for example, the silicone lens may be formed between the limiting sides of the reflector. The silicone lens of the secondary optics can be made, for example, from a second potting material with a refractive index n2, where n1 can not be equal to n2. In general, the primary optics and / or the secondary optics can be produced according to the invention.

The object underlying the invention is also achieved by an optoelectronic chip-on-board module, comprising a flat carrier, which is equipped with one or more optoelectronic components, with a transparent, UV and temperature-resistant coating of a silicone which is characterized in that a surface of the carrier, which is equipped with one or more optoelectronic components, is borderless coated with the silicone.

This optoelectronic chip-on-board module according to the invention has the same advantages as the method according to the invention described above, since it is borderlessly coated with a silicone which is transparent, UV-resistant and temperature-resistant. The entire surface of the carrier is available for the arrangement of optoelectronic components, so that the design freedom is maximized.

Preferably, the carrier is also coated on its side surfaces at least partially with the silicone, so that the protection of the chip-on-board module is further increased.

In an advantageous development, the silicone has an admixture of optically functional materials, in particular phosphorescent and / or scattering materials or particles. This makes it possible to adjust the wavelengths and color properties of the material, in particular if the optoelectronic chip-on-board modules are light-generating modules, for example LED modules and / or UV LED modules.

Likewise advantageously, the coating has a surface structure, in particular lenses, preferably microlenses, or light-scattering roughenings. This surface structure can be produced by molding from the mold or by subsequent processing.

In a further, alternatively or additionally realizable embodiment, the coating has at least one optical component. With respect to possible embodiments of the optical component, reference may be made to the above description. In particular, one or more optical elements may be included, for example, as primary and / or secondary optic elements having at least one effect selected from the group consisting of a collecting action, a scattering effect, a diffusive action and a diffractive action. For example, one or more optical elements may be included as primary optic and / or secondary optic elements selected from the group consisting of a condenser lens, in particular a convex lens, a diffuser lens, in particular a concave lens, a reflector, a diffuser, an optical grating, a Hologram. Combinations of said and / or other optical elements may also be included. In particular, one or more of said optical elements may be arranged as an array. For example, the coating may comprise at least one array which contains a plurality of said optical elements of the same or different type. In the context of the present invention, the array can be produced in the form of a surface structure by molding it out of the mold. In particular, the coating may have at least one lens and / or at least one lens array.

For example, the coating may comprise at least one lens array. This lens array may comprise a plurality of lenses whose dimensions may be adapted to the particular application. Thus, lenses may be included which, in their diameter or equivalent diameter when viewed from top to bottom of the carrier, have dimensions which may be from a few microns or a hundred microns to decimetres. In particular, the lens array may be wholly or partially equipped as a microlens array and may comprise one or more microlenses, for example with dimensions in the sub-millimeter range. In general, the optics may comprise, for example, at least one micro-optical element and / or at least one micro-optic. As stated above, the sizing of the optics and / or optical elements may be generally adapted to the application. For example, one or more optical elements may be included, for example one or more lenses, in particular within a lens array, which have a diameter of 1-10 mm, typically a diameter of 2-4 mm, typical for optoelectronic components such as LEDs. For example, typical high-power LEDs have an emission area of 1 mm ² , which can be completely or partially covered by the dimensions of the optical elements mentioned.

The optics, in particular one or more optical elements of the primary optics and / or the Secondary optics, may have changes in curvature, especially on local areas or subregions, for example on a scale in the sub-millimeter range. On this sub-millimeter scale, the optics can thus influence locally adjacent beam paths of parallel incident light. For example, curvature structures with equivalent local radii in the sub-millimeter range can be used as one or more optically active elements of primary optics and / or secondary optics.

As stated above in the context of the description of the method, the chip-on-board module can have at least one primary optic adjacent to the at least one optoelectronic component and optionally at least one secondary optic. At least one optic selected from the group consisting of the primary optics and the secondary optics can be formed at least partially in the coating, in particular in a surface structure of the coating.

As stated above, the at least one coating, for example the first coating and / or the second coating, may in particular comprise at least one silicone. The coating and the optoelectronic chip-on-board module can be produced or coated in particular by means of a method according to the invention. In general, the primary optics and the optional secondary optics may be formed in the same at least one coating. Alternatively, the primary optics may also be formed in at least one first coating and the secondary optics may be formed wholly or partly in at least one second coating, which may be different from the first coating. In particular, the primary optics and the optional secondary optics can also be formed using different coatings with different refractive indices. For example, as described above, the primary optics may be wholly or partially formed in at least a first coating, for example a first silicone coating, with a first refractive index n1, and the secondary optics may be wholly or partially formed in at least one second coating having a second refractive index n2 ≠ may have n1. The coatings can be applied successively, for example, in different coating steps, wherein, for example, one or both of the coatings can be applied to the optoelectronic chip-on-board module using a coating method according to the invention.

For further possible embodiments of the primary optics and / or secondary optics, which may be formed individually or both wholly or partly in the coating, reference may be made to the above description of the method.

The carrier is preferably equipped with optoelectronic components up to an edge or until shortly before an edge. This also includes the possibility that the carrier is equipped with optoelectronic components up to several or all edges or until shortly before these edges. This allows the effective utilization of the entire available surface of the carrier, since the edge does not have to be released, since a vacuum seal as known from the prior art, is eliminated. This allows a consistent pitch of optoelectronic components to be maintained across the boundaries between adjacent modules.

The optoelectronic chip-on-board module according to the invention is preferably produced or producible by a method according to the invention as described above.

Furthermore, the object underlying the invention is also achieved by a system having two or more optoelectronic chip-on-board modules described above, wherein the carriers of the optoelectronic chip on-board modules are arranged flush with each other or with a defined distance from one another , wherein in particular due to marginal placement of the carrier with optoelectronic components results in a regular across the boundaries between adjacent carriers and spacing of optoelectronic components. In this case, a defined distance is generally understood to mean a selected fixed and, as a rule, location-dependent, constant distance between two adjacent modules. This is to be chosen, for example, to take account of material tolerances in order to ensure manufacturability or to achieve certain lengths of the system, for example a lamp.

The properties, features and advantages of the invention, that is to say the method according to the invention, the optoelectronic chip-on-board module according to the invention and the system according to the invention, also apply unrestrictedly to the respective other subjects of the invention.

The proposed method, the optoelectronic chip-on-board module and the system can be used advantageously in numerous ways. For example, irradiation devices with high irradiance in chip-on-board technology can be realized in this way. From the prior art are due to the typically necessary small distances between the LEDs (so-called pitch) only a few methods known with which ever beam-shaping microlenses on the individual LEDs of an LED array can be realized by a potting material. Likewise, the targeted influence of a position-dependent adjustment of the radiation characteristics of the individual microlenses (optics) in an array arrangement in front of the LED spotlight and in the edge area with previous methods is virtually impossible. However, such structures are easily possible by means of the proposed method. In particular, microlens primary optics and / or microlens secondary optics for LED arrays can be realized, wherein the secondary optics can be optimally matched to the primary optics and / or vice versa. The combination of this primary optics approach and one or more secondary optics opens up new concepts for increasing the irradiance at significant working distances of> 10 mm with respect to the light emission window of the LED spotlights.

By means of the proposed method, in particular an individual shaping of individual lenses, in particular microlenses, over one, several or all optoelectronic components, in particular the LEDs of an LED array configuration, is possible. In this way, for example, a radiation characteristic of an entire LED array can be selectively influenced, for example for the purpose of homogenization and / or beam focusing.

As stated above, the proposed method can be used in particular for the production of optoelectronic chip-on-board modules and systems which have at least one primary optics and optionally at least one secondary optics. In this case, the primary optics and / or the secondary optics can wholly or partly be produced according to the invention in which the primary optics and / or the secondary optics are formed in the silicone or the coating.

Systems with primary optics and secondary optics are known from the prior art conceptually from other areas and can now be realized and manufactured according to the invention. For example, the use of secondary optics, for example for already packed LEDs (eg LEDs in an SMD housing), is basically known. Furthermore, LEDs are used in reflector housings (assembled) and sealed housing with a potting material having optical properties for beam shaping, such. B. the shaping of the potting material to lenses. Such housings are already partially available on the market. However, in most housed LED products, the optical functionality of the package includes only a beam-shaping optical variant, either a reflector realized by a recess into which the LED is inserted, or a lens, the LED then typically being mounted on a flat substrate becomes. For these components, if necessary, a further secondary optics (lens or reflector, or a combination of both) is placed over the gehausten LEDs. For LED arrays is the use of micro-reflectors in US 7,638,808 described. In this case, a substrate is used which has cavities in which LEDs are used. Side walls of these individual cavities serve as a reflector, which can be customized. Likewise, the use of an additional beam-forming potting, with which the cavities are sealed, is described. Thus, it is a combination of micro-primary lens and micro-primary reflector, for individual LEDs in an array arrangement. Even such known concepts, which can be realized only comparatively complex with conventional methods, can be realized simply and reliably with the method proposed according to the invention.

Furthermore, according to the invention, concepts can be realized with primary optics and secondary optics, in which one or more secondary optics are used, which further bundle the light, for example, from a plurality of light-emitting diodes each having associated micro-primary optics. These optics can be placed, for example, on LED arrays, segments of LED arrays, photodiode arrays or segments of photodiode arrays, so that, for example, a secondary optics includes a plurality of LEDs of an LED array with micro-optics.

The invention can be used in particular in the field of radiation technology and the exposure technique, for example in industrial processes. In industrial processes, there are a variety of LED exposure and radiation applications, especially in the ultraviolet and infrared spectral range. Numerous examples may be mentioned here, such as, for example, drying of inks, application of irradiation in the field of UV curing, for example, adhesives, inks, paints, varnishes and potting materials, as well as use in exposure applications.

In particular, by means of the present invention, the requirements typically applicable for irradiation applications can be realized well. The basic requirements are usually that in the wavelength range used, a high or an adapted to the particular application irradiance is feasible, typically irradiances from a few 10 μW / cm ² to several tens or a few hundred W / cm ² in an adjustable distance of typically a few millimeters to a meter or more can be realized. At the same time, certain light distributions necessary for the respective process should typically be achievable. The light distribution can be, for example, a homogeneous field distribution in a specific process window or a narrow line. For example, current applications in the printing industry include ink jet, sheet offset, screen printing, gravure and flexographic printing. For sheet-fed printing processes, high irradiance levels of 2-20 W / cm ² at intervals of 20-200 mm are generally required for ultraviolet LED light in the range of 360-420 nm.

The minimum requirement for the irradiance required for the respective process is generally also material-dependent. For UV curing applications, for example, usually photoinitiators are used, which usually allow a sufficiently rapid reaction to chain the monomers (polymerization) only when a threshold value of the irradiance is exceeded, so that a good curing result is achieved. This plays. For example, in the case of surface hardening, inhibition by oxygen also precludes polymerization.

The basis for an efficient realization of high-power LED spotlights, which can have a multiplicity of LED chips and which can have optical powers of a few W up to several 10 kW and which furthermore generally have to meet special requirements for the respective lighting profiles , is as high as possible, efficient light output from a minimum necessary radiation surface. Efficient and compact spotlights have emission areas of a few cm ² up to a few hundred cm ² . In order to achieve the necessary high packing densities of, for example, up to 20 pcs. 1 mm ² large LED chips / cm ² and keep the, due to the typical efficiencies of UV LEDs in the range of 1-50% associated high thermal loads as low as possible To be able to use well optoelectronic chip-on-board modules according to the invention and system according to the invention with a plurality of optoelectronic chip-on-board modules. For example, chip-on-board modules are currently being developed with optoelectronic components in the form of chips having an area of 1.3 × 1.3 mm ² . Future developments can expect modules with chips up to several mm ² chip area.

Light emitted by light-emitting diodes is generally divergent due to the LED-typical radiation characteristic. Modern LEDs are typically surface emitters which radiate into the half-space and usually have the radiation characteristic of a Lambertian radiator. By this divergent radiation characteristic results in a strong dependence of the irradiance on the working distance, so for example in the distance between the object to be irradiated and the optoelectronic chip-on-board module, in particular the LED spotlight. According to the invention, however, the emitted light of LEDs in an LED array configuration can be used efficiently and realize a high irradiance even at large working distances. In particular, adapted optics can be realized which on the one hand can maximize the coupling out of the light from the optoelectronic chip-on-board modules, in particular the LED chips, and on the other hand can generate a high irradiance and a defined field distribution at a specific working distance.

For very large working distances, for example working distances of at least 20 mm, in particular the emitted light can be strongly collimated. The use of primary optics without further optics, however, usually reaches its limits, since the LED can not be regarded as a point light source in the case of microlens optics. This is due in particular to the fact that the size of the lens, which typically has a diameter of 1-10 mm, and the size of the LED, which typically has an edge length of 1 mm, are comparable. Therefore, as a rule, the light can not be completely collimated, and with increasing collimation, the efficiency of the lens also decreases due to reflection losses in the lens. For an optimized solution, therefore, for example, in addition to at least one optimized primary optics, with very high requirements on the irradiance and the working distance according to the invention at least one additional secondary optics can be realized to achieve high collimation or even focusing of the light and to maximize system efficiency ,

In particular, at least one secondary optic can be realized, which is in the form of a reflector optic having at least one reflector or in the form of a combination of at least one reflector optic and at least one lens optic. In this combination, the light that can not be directly directed by the primary optics in the irradiation field, for example, "collected" by the reflector and deflected into an irradiation field. Furthermore, in an implementation according to the invention, primary optics can be optimized for secondary optics and vice versa, so that bilateral adaptation of primary and secondary optics is possible.

According to the invention, in particular for influencing a directional characteristic, in particular a radiation characteristic of the light emitted by the LEDs, at least one optical system can be used. Accordingly, as stated above, the optoelectronic chip-on-board module according to the invention and / or the inventive System have at least one optic. When using a plurality of optics can, as stated above, be distinguished between primary and secondary optics. For example, the primary optics may comprise a lens array of a transparent potting material which, for example by means of a method according to the invention, can be applied directly to the carrier equipped with the optoelectronic components, for example the LEDs, so that the primary optics are firmly connected, for example, to the LED chips can be. For example, for UV LEDs, a UV-stable, thermosetting silicone may be used, alternatively or additionally, using other materials is conceivable, for example, the use of light-curing acrylates, PMMA, polycarboxylate or other materials or combinations of the above and / or other Materials. As stated above, the term primary optics is used regardless of whether or not this primary optic is combined with another optic.

According to the invention, numerous optically functional geometries can be realized, for example lens shapes and / or scattering forms. These geometries can be adapted to those for generating the respectively necessary irradiance profiles for the applications. Only molds with a significant undercut are generally difficult to realize, since the process according to the invention is a casting process. However, for example, forms are well-suited to be selected from: spherical lens optics, in particular in the form of cylindrical and / or rotationally symmetrical optics, both symmetrical and asymmetrical shape; Aspherical optics, in particular in the form of cylindrical and / or rotationally symmetrical optics, both symmetrical and asymmetric shape; Free-form optics, in particular in the form of cylindrical and / or rotationally symmetrical optics, both symmetrical and asymmetrical in shape; Fresnel optics, in particular in the form of cylindrical and / or rotationally symmetrical optics, both symmetrical and asymmetrical shape; polygonal and / or faceted optics, in particular in the form of cylindrical and / or rotationally symmetrical optics, both symmetrical and asymmetrical shape; rough structures, for example for light scattering or for randomly distributed light diffraction; Structures with a structured surface. Combinations of the mentioned forms and / or other shapes are possible.

The possibility of realizing a primary optic offers several functions and advantages. In particular, at least one lens can be positioned directly above an optoelectronic component, for example directly above an LED. As a result, the lens has, in contrast to a lens in the usual sense, only one exit side and no entry side, since the light emerging from the LED can enter directly into the material of the lens. This leads to an increase in the outcoupling efficiency of the light from the LED or from the system, since the light has to pass through an interface less and the refractive index adjustment between LED and potting leads to a reduction of total internal reflection within the LED, but also in comparison to the total reflection in a plan potting.

Due to the geometry of the lens, reflection losses at the interface between encapsulation and air can furthermore be deliberately minimized. This causes, for example, in comparison to a plan Verguss a further increase in efficiency. For silicone, an increase in the extraction efficiency is generally possible in comparison to a plan casting of about a factor of 2.

For each individual optoelectronic component, for example, for each individual LED, a beam shaping adapted to the objectives can be generated, so that both an optimization of the geometry of the optics, for example, the lens geometry, taking into account the direct steering of the light in the target irradiation surface, as well can be carried out in terms of Auskoplungsseffizienz and also on the adaptation to the properties of a secondary optics.

Furthermore, lens surfaces spatially seen very close, for example, at a distance of less than 1 mm, to the optoelectronic components, such as the LEDs are arranged. As a result, for example, the light of a large solid angle range, in particular up to a solid angle range of more than 70 °, can be exploited, which can increase efficiency and enable high power densities.

The encapsulation or the coating, in particular the silicone encapsulation, protects the optoelectronic components, in particular the LEDs, from external influences such as dirt, moisture and mechanical influences.

Furthermore, the potting material usually has a higher refractive index than air. Thus, the refractive index of the potting material is typically n> 1, for example n = 1.3-1.6. As a rule, this results in a refractive index adaptation between the semiconductor material of the optoelectronic components, in particular of the LED chip, whose refractive index is typically at n = 3-4, and the potting material. As a result, the light extraction from the optoelectronic chip-on-board module is improved and the overall efficiency is positively influenced.

Alternatively, or in addition to using one or more lenses in primary optics, the primary optic may further include one or more reflectors. For example, the primary optics can have a microreflector array in which, for example, each optoelectronic component, for example each LED, can be arranged in a small cavity whose reflective walls form the microreflector. Array primary optics comprising a combination of at least one microlens and at least one microreflector is also possible.

In an analogous manner, the at least one optional secondary optics can also be realized, for example, in the form of one or more refractive elements, for example one or more lens elements, and / or in the form of one or more reflective elements.

Depending on the application process, the requirements for the emitted light may also vary. If, for example, an arrangement of substrates or carriers is used in a continuous process, it is generally important to realize a homogeneous and intensive irradiation intensity, while in the direction of travel, as a rule, essentially to maximize the dose rate of Meaning is. Specifically, this means, for example, in the case of a line radiator, that it may be advantageous to position the LEDs in a spatial direction very closely, for example at a distance of 0.05-5 mm, while it may be more appropriate in the orthogonal spatial direction To increase the distance between the LEDs, for example, to more than 1 mm, in this way, for example, to obtain space for efficient collimating primary and / or secondary optics. By contrast, a uniform distribution of the optoelectronic components, for example, a uniform LED distribution, usually for the realization of a surface radiator, which is to illuminate a surface homogeneous, be favorable.

In general, according to the invention, the same or different or also position-dependent different geometries can be realized. For example, distances between the optoelectronic components, for example the LEDs, and / or the microlenses can be realized in one or both spatial directions within an array. Thus, a distribution of the optoelectronic components and / or a distribution of the elements of the primary optics and / or the secondary optics, for example a microlens distribution, can be considered and used in the development of an efficient component, for example an efficient LED emitter.

Furthermore, a structure size primary optics and / or secondary optics, for example, a structure size of the lenses of the primary optics and / or secondary optics, can be variably adjusted, for example, to the respective application. Different possibilities can be realized individually or in any combination. Thus, the optoelectronic components, for example the LEDs, and components of the primary optics and / or secondary optics, for example the lenses, can have comparable structural sizes. This may mean, for example, that each optoelectronic component, for example each LED, has an associated element of primary optics and / or secondary optics, for example an associated lens. The maximum structure size of the elements of the primary optics or the secondary optics, for example the maximum structure size of the respective lens, is generally limited by the pitch of the optoelectronic components, for example the LEDs.

Furthermore, as an alternative or in addition, embodiments can also be realized in which the structure size of individual, several or all optoelectronic components is smaller than the structure size of the optics, for example the primary optics. For example, embodiments can be realized in which the structure size of the LED is smaller than that of the associated lens. This can then mean, for example, that a lens and / or another component of the primary optics and / or the secondary optics extends over a plurality of optoelectronic components, for example via a plurality of LEDs.

Furthermore, as an alternative or in addition, embodiments can also be realized in which the structure size of individual, several or all of the optoelectronic components is greater than the structure size of the optics, for example the primary optics. For example, embodiments can be realized in which the structure size of the LED is greater than that of the lens. This can then mean, for example, that several elements of primary optics and / or secondary optics, for example a plurality of lenses or a lens array, are located in front of an optoelectronic component, for example in front of an LED.

Furthermore, within an array, the ratios of the structure sizes of the optoelectronic components and / or the optics can also vary in one or both spatial directions. Thus, the conditions in both spatial directions may be the same or different or even change in the course.

As stated above, the optics may be diffusive and / or collimating and / or focusing Have functions. For example, a lens function of the primary optics can be provided, which is designed to be scattering, collimating or focusing. If only one primary optic is used, then it is generally advantageous if it is designed to be collimating or focusing. When using a reflector as a secondary optics, however, it may be useful, for example, in terms of efficiency and functionality of the overall system to interpret the primary optics scattering so as to make the best possible use of the reflector.

A distance between the optoelectronic component, for example the LED, and the primary optics usually also determines which portion of the light, for example the light emitted by the LEDs, can be influenced by primary optics, in particular the lenses, and how the effect on this light is. The distance may decide whether the light is scattering or collimating. Within an array, the distance between the optoelectronic component, such as the LED, and the lens may be the same or vary. For a given lens size, an acceptance angle, also referred to as numerical aperture NA, may depend on the distance from the lens to the optoelectronic component, for example LED. Light that is emitted outside this acceptance angle is scattered at the edges of the lens or the neighboring lenses and / or broken uncontrollably, so that this is classified as a loss component. For this reason too, the distance between the optoelectronic component, for example the LED, and the surface of the primary optics can be relevant.

Furthermore, the size of the solid angle in which the primary optics and / or the secondary optics can exert influence on the beam path of the emitted or incident light, for example of the light emitted by the LEDs in the half-space, is usually a relevant measure of the efficiency the optics. In order to improve this efficiency, therefore, the available optically effective surface area of the optic should usually be maximized. A measure which can be implemented according to the invention may be to take into account rectangular or polygonal basic and sectional surfaces instead of easily formed, round base surfaces and rotationally symmetric horizontal sectional surfaces which maximize the available surfaces between adjacent optoelectronic components, for example between adjacent LEDs , For an array with the same pitch in both spatial directions, this corresponds, for example, to a square basic form. With maximum utilization of, for example, square footprint, the optically active area can be maximized, which can translate into an increase or even maximization of efficiency.

The surface of the primary optics may be smooth, roughened or otherwise structured, wherein in the latter case, for example, the surface may also be provided with Fresnel optics. With a smooth surface, for example, as a rule, the actual lens effect is not influenced. In a targeted shaping, such as collimation, can be achieved with this surface in many cases, the greatest efficiency. With a roughened and / or microstructured structure, an additional scattering effect is usually added to the actual lens effect.

If lenses are used in optics, for example primary optics, they can be aligned in various ways with the associated optoelectronic components. Thus, for example, a lens center of a lens of the primary optics can be aligned centrally or decentrally to an associated optoelectronic component, for example to an LED. A decentration, for example in the micrometer to millimeter range or larger, can be specifically for all lenses the same or sliding shifted. By such shifts a light cone shaped by the primary optics can be tilted, for example. As a result, for example, a so-called squint effect for increasing the irradiance in the center in front of the LED array can be achieved by, for example, directing the light cone of the LEDs located at the edge to the center by such a relative displacement. A statistically distributed relative shift within an LED array can also be used to homogenize the light.

As stated above, at least one primary optic can be combined with at least one secondary optic. The secondary optics may for example comprise at least one reflector and / or at least one lens, wherein said elements may be arranged individually or in an array. For example, the secondary optics may include, for example, a reflector array and / or a lens array. Especially at long intervals usually contributes to the use of primary optics only the light of a relatively small solid angle range for lighting. The secondary optics also make the light of an enlarged solid angle range usable, which can increase the efficiency of the overall system. This allows two effects or a blending effect of both effects to be achieved. Thus, the secondary optics, a focusing of the light can be significantly improved. This has the advantage that with a constant number of optoelectronic components, for example in constant number of LEDs, the maximum irradiance can be increased. If the maximum irradiance should remain at the same level, the number of optoelectronic components, for example the number of LEDs, can be reduced, since the existing light can be used more efficiently by the secondary optics.

The primary optics can also be combined, for example, with at least one reflector and / or at least one further lens array as secondary optics. As a result, it is usually possible to further transform the field distribution generated by the primary optics. It is thus possible, for example, to achieve an improved focus in order to increase the maximum irradiance.

• a. Primär- und Sekundäroptik besitzen vergleichbare Strukturgrößen.
• b. Die Strukturgröße der Primäroptik ist kleiner als die der Sekundäroptik.
• c. Die Strukturgröße der Primäroptik ist größer als die der Sekundäroptik.

Depending on the application process, the secondary optics can also be designed in such a way that they act in one or both spatial directions. In concrete terms, in the case of a line radiator for a continuous process, this can mean that the secondary optics can be arranged orthogonal to the direction of rotation and can serve to increase the dose rate and the maximum irradiance in the target area in the direction of travel. For example, the primary optics in a surface radiator can also be designed as a grid, or be formed in a line emitter as parallel line (reflector) profiles. This may mean that the structure size of the secondary optics can also be variably adjusted. Several possibilities can be realized:

• a. Primary and secondary optics have comparable structure sizes.
• b. The structure size of the primary optics is smaller than that of the secondary optics.
• c. The structure size of the primary optics is larger than that of the secondary optics.

Within the radiator, the ratios of the feature sizes in both spatial directions may be the same or different or may change over time.

In order to be able to serve different process areas, in each case size-adapted carriers, in particular substrates, can be designed. In order to keep cost and effort low, it is usually useful to string identical substrates, for example, with an area in the range 1 cm ² or greater, to each other. Therefore, a modular structure of the system according to the invention, for example, the LED system, and the optical concept can be realized. Also with respect to this realization, in turn, several variants exist. Thus, for example, a series of two or more inventive optoelectronic chip-on-board modules in a spatial direction or in two spatial directions. An encapsulation can be realized simultaneously for one, two or more optoelectronic chip-on-board substrates or chip-on-board modules. The potting can for example be applied without lateral projection on the carrier, for example the substrate, so that a continuous stringing together of carriers is possible.

Furthermore, for example, one or more optoelectronic chip-on-board modules and / or their carriers and / or one or more systems according to the invention can be arranged on one or more heat sinks, or an optoelectronic chip-on-board module and / or a System according to the invention may comprise one or more heat sinks. For example, one or more chip-on-board substrates with LEDs may be on a heat sink / carrier. In the potting process, for example, at least one heat sink can be provided with a potting, so that, for example, all the carriers located thereon can be potted simultaneously. A simultaneous joint encapsulation of several heatsinks, which can act as a module base, is also conceivable.

A modularity of the secondary optics can generally also correspond to a modularity of the optoelectronic components, for example a modularity of the LED array, so that, for example, an array of optoelectronic components, for example an LED array, contains a secondary optics module.

If secondary optics modules are provided, they may be larger or smaller than an array of the optoelectronic components, for example as an LED array, so that, for example, a secondary optics module is positioned over two, three or more arrays of optoelectronic components, for example LED arrays, arranged side by side can. In the opposite case, for example, two, three or more secondary optics modules per array of the optoelectronic components, for example per LED array, may be required.

An optional juxtaposition of optoelectronic chip-on-board modules and / or carriers thereof, for example in a system according to the invention, and / or a juxtaposition of secondary optics can, based on the distance of the optoelectronic components, pitch-preserving, so directly aligned, or even non-pitcher-holding, that is, it can be arranged with an interval between.

Within an optoelectronic chip-on-board module or a system, for example within an LED emitter, differently shaped secondary optics can be used. So For example, at the edge of an optoelectronic chip-on-board module, in particular at the edge of an LED emitter, reflectors may be used which reflect the light obliquely, for example, to a center in front of the emitter, for example similar to the "squinting" primary optics described above. The central reflectors can also reflect the light to the center in front of the spotlight.

Furthermore, depending on the position, different secondary optics can be used, for example at least one reflector, at least one lens or at least one combination of at least one reflector of at least one lens. Alternatively, secondary optics can also be dispensed with entirely depending on position.

Overall, it is possible according to the invention to realize optoelectronic chip-on-board modules, which preferably have at least one primary optic which, for example, has only one exit side. Reflection losses at an entrance side can be avoided in this way. Furthermore, a shaping, for example a use of an optical form of a lens can take place, which can reduce reflection losses. For each individual optoelectronic component, for example for each individual LED, a beam shaping adapted to the target specifications can be generated. Due to the possibility of a spatial proximity of the optics to the optoelectronic components, for example the lenses to the LEDs, the light of a large solid angle range can be used.

Furthermore, the optoelectronic components, for example the LEDs; receive a protective, transparent, UV and temperature-stable potting. In this way, in particular, a long-term stability can be improved, and due to an increased impermeability to moisture and other environmental influences, new applications can be opened up.

Due to the possibility of a variably adjustable distance between the optoelectronic components, for example between the LEDs, in one or both spatial directions, the available light output can continue to be adapted exactly to the respective requirements. For example, many LEDs can be arranged in a small space, or comparatively fewer LEDs can be arranged in order to generate space for a particular optical system.

The various possible structure sizes of the elements of the primary optics, for example, the lenses of the primary optics, the existing light output can be used efficiently. For example, a lens function of the primary optics can be designed to be scattering, collimating or focusing as required. The surface of the primary optics can be designed, for example, smooth, roughened or otherwise structured as needed.

By the possibility of a shift of the elements of the primary optics relative to the associated optoelectronic components, for example by a shift of the lens of the primary optics relative to the LED, as described above, a beam cone can be inclined (squint).

By using one or more optional secondary optics, the efficiency of the optoelectronic chip-on-board module and / or the efficiency of the system can be significantly increased. In particular, a "recycling" of divergent light can be realized in this way. As a result, higher irradiation intensities can be achieved, for example, and / or optoelectronic components, in particular LEDs, can be economized.

Another advantage of the present invention is the possibility of realizing high modularity. Thus, for example, optoelectronic chip-on-board modules with one or more one-dimensional or two-dimensional arrays of optoelectronic components can be realized, wherein these arrays can be designed identically. Several such optoelectronic chip-on-board modules, in particular with identical arrays of the optoelectronic components, can be connected to one another in one or two spatial directions. The identity of the arrays of the optoelectronic components, for example the LED arrays, can be advantageous for a simple and cost-efficient production process. Overall, advantages in terms of adaptation to different process geometries can be achieved in this way.

These individual advantages that can be realized according to the invention or combinations of these advantages can bring about a direct increase in efficiency of the optoelectronic chip-on-board module and / or of the system, for example of the radiator. As a result, it is possible, for example, to achieve very high irradiation intensities with homogeneous irradiance distributions even at long intervals. The listed benefits can be combined in pairs or in any group. The range of possibilities to be realized is thereby high, whereby a multiplicity of demands can be fulfilled.

The invention is hereinafter without limiting the general inventive concept by means of embodiments below Reference is made to the drawings, with reference to all unspecified in the text details of the invention, reference is expressly made to the drawings. Show it:

1 a schematic representation of two chip-on-board LED modules,

2 a schematic representation of a chip-on-board LED module according to the invention,

3a) . 3b) a schematic representation of the method according to the invention,

4 a schematic representation of another chip-on-board LED module according to the invention,

5 a schematic representation of another chip-on-board LED module according to the invention,

6 a schematic representation of another chip-on-board LED module,

7A and 7B Embodiments of chip-on-board modules according to the invention with different primary optics;

8A and 8B : Further exemplary embodiments of realizable chip-on-board modules with different types of primary optics for a plurality of optoelectronic components;

9 FIG. 2 shows a further exemplary embodiment of a chip-on-board module with a primary lens system with a plurality of lenses per optoelectronic component, FIG.

10A and 10B : Exemplary Embodiments of Chip On-Board Modules with Oriented Primary Optics ( 10A ) and staggered primary optics ( 10B )

11 FIG. 1: an exemplary embodiment of a chip-on-board module with primary optics and secondary optics that can be realized according to the invention,

12 : one too 11 alternative embodiment with primary optics and secondary optics,

13 a representation of the light path in the embodiment according to 11 .

14 : An embodiment of a chip-on-board module with multiple secondary optics, and

15A to 15C : Various embodiments of inventive optoelectronic modules with different surface structure.

In the following figures, identical or similar elements or corresponding parts are provided with the same reference numerals, so that a corresponding renewed idea is dispensed with.

The invention is explained on the basis of chip-on-board LED modules, that is to say with reference to luminous bodies, as an example of optoelectronic chip-on-board modules. In the context of the invention, photodiodes in solar cells or other components can be used instead of LED modules as optoelectronic components.

In 1 is a chip-on-board LED module 1 schematically shown without coating in cross-section, in which on two parallel carriers 2 . 2 ' or substrates printed conductors 3 . 3 ' and designed as unbehauste LED chips LEDs 4 . 4 ' are arranged at regular intervals. For the sake of clarity, not all recurring elements are the 1 and the following figures with reference numerals, however, these relate to all similar elements. It is, therefore in 1 only one LED at a time 4 . 4 ' for each of the two chip-on-board LED modules 1 . 1' provided with a reference number. The other components are identical.

A carrier 2 . 2 ' For example, it may be a metal, ceramic, or silicon substrate constructed in rigid, semi-flexible, or flexible substrate technology, a metal core or FR4 circuit board, a glass carrier, or a plastic carrier.

With lines are light cones 5 . 5 ' the LEDs 4 . 4 ' shown. The LEDs are approximately Lambertian emitters, which radiate about 75% of the total radiated light output within an opening angle of 120 °. Is that with LEDs 4 . 4 ' equipped area extended compared to the measuring distance and the distance sufficiently larger than the distance of the LED chips, also called "pitch", then a homogeneous intensity distribution is measured with similar properties, such as a homogeneous, diffuse luminous surface.

Im in 1 In the case illustrated, the homogeneous intensity distribution also settles over the joint 6 between adjacent modules 1 . 1' away, because the overlap area 7 the light cone 5 . 5 ' at this point due to the regular and marginal placement of the carrier 2 . 2 ' with LEDs 4 . 4 ' and the absence of optical obstacles is well formed.

In 2 is an inventive chip-on-board LED module 11 shown schematically on a support 2 also tracks 3 and LED chips 4 having. It is with a silicone coating 12 provided in peripheral areas 13 also over the side edges of the carrier 2 reach out and the carrier 2 thus protect all around.

The chip-on-board LED modules according to the invention 2 according to 2 can be arranged flush next to each other, so that a uniform overlapping radiation area with a radiation characteristic as in 1 shown, is achievable.

In 3a) and 3b) is shown schematically how the inventive chip-on-board LED module 11 according to 2 will be produced. First, an uncoated chip-on-board LED module 1 upside down in a form 20 with a bath of liquid silicone 21 dipped, which consists of one or more silicone supplies 22 had been poured into the mold. The immersion happens in the direction of the arrow in the center 3a) ,

The filling level of the silicone is chosen such that the carrier 2 with its surface touches the surface of the silicone or slightly immersed in it. For the dimensions or the clear inside dimension of the form are chosen such that the carrier 2 of the chip-on-board module 1 completely absorbed in the mold. Between the sidewalls of the form 20 and the outside of the carrier 2 If necessary, there is a small gap in the silicone 21 can penetrate.

The liquid silicone 21 is then cured and crosslinked with the module, for example thermally. When the silicone has fully cured, the carrier becomes a newly coated chip-on-board LED module 11 including the now hardened, adhering and transparent encapsulant removed from the mold. This is in 3b) with the arrow shown centrally in it.

In the 4 . 5 and 6 are three different variants of optoelectronic chip-on-board modules according to the invention 11 ' . 11 '' . 11 ''' shown in the components of the carrier, the trace and the LEDs are not from the chip-on-board LED module 11 out 2 differ.

In 4 indicates the surface of the coating 12 a surface structure in the form of lenses, in particular microlenses, made of silicone over the individual LEDs, which results from an inverse molding of the structure from the mold into which the silicone had first been introduced. These lenses act as a bundling or scattering light for the light emitted by the LEDs, depending on the geometry set.

In the 4 The structure shown can also be used by photovoltaic modules to focus incident light on the corresponding photodiodes.

In 5 is in the optoelectronic chip-on-board LED module 11 '' the surface changed so that a roughened surface texture 16 results. As a result, the light emitted by the LEDs is scattered in different directions and the light distribution is homogenized as a whole.

In 6 is in a chip-on-board LED module according to the invention 11 ''' a surface structure of the coating 12 set that off 4 with single lenses 15 matches over the LED chips. In addition, the silicone compound with phosphorescent material 17 which causes a wavelength shift of the emitted light or a part of the emitted light, which by the above the lenses 15 shown tortuous arrows is shown with different wavelengths. These arrows symbolize photons of different wavelengths and thus of different colors. For example, the small meandered arrows may correspond to photons from the ultraviolet region, while the larger arrows may correspond to photons in the visible region.

All mentioned features, including the drawings alone to be taken as well as individual features that are disclosed in combination with other features are considered alone and in combination as essential to the invention. Embodiments of the invention may be accomplished by individual features or a combination of several features.

In the 7A to 15C various further embodiments of inventive chip-on-board modules are shown, which without limitation of other possible embodiments in these figures with the reference numeral 11 are designated. For the design and manufacture of these chip-on-board modules 11 can be referred to the above description by way of example.

So can the chip-on-board modules 11 , as shown above, have one or more optics, which in the following generally designated by the reference numeral 23 be designated. The above-mentioned lenses 15 represent examples of such optics 23 As an alternative or in addition to lenses, however, other optics may also be used, for example reflectors. In the following, generally between a primary optic 24 and one secondary optics 25 distinguished. As stated above, being under a primary optic 24 an optical element understood, which on a light path the optoelectronic components, in the illustrated embodiments, the LEDs example 4 , is located adjacent, so that between the primary optics 24 and the optoelectronic components, in particular the LEDs 4 , no further optical components with scattering, collecting or collimating properties are arranged. Under a secondary optic 25 On the other hand, an optical component is understood which is relative to the optoelectronic components, here the LEDs 4 is arranged such that at least one further optoelectronic element with scattering, collecting or collimating properties is arranged on an optical path between these elements and the optoelectronic components. This may be the primary optics 24 and / or the secondary optics 25 be designed according to the invention by means of the method according to the invention. The primary optics 24 and / or the secondary optics 25 may each comprise one or more optical components, such as lenses and / or reflectors.

In the 7A and 7B are exemplary embodiments of optoelectronic chip-on-board modules 11 which are each exclusively primary optics 24 include. It shows 7A an embodiment in which in an array of LEDs 4 one LED each a lens 15 assigned. The LEDs 4 and the respective associated lenses 15 the primary optics 24 have comparable structure sizes.

In 7B however, an embodiment is shown in which the primary optics 24 , in addition to lenses 15 , Reflectors 26 includes. For example, these reflectors 26 be designed as micro-reflectors. For example, the reflectors 26 are each configured as depressions, for example as depressions in the carrier 2 , wherein the surfaces of these recesses may have reflective properties. Again, for example, a structure size of the reflectors 26 and / or the lenses 15 in the 7B illustrated embodiment comparable to the size of the chips of the LEDs 4 be.

In the 8A and 8B are further embodiments of optoelectronic chip-on-board modules 11 each showing a primary optic 24 exhibit. In this embodiment, the primary optics 24 each in turn lenses 15 auf, analogous to the embodiment according to 7A , Here, however, each is a lens 15 several LEDs 4 assigned. The structure size of the LEDs 4 is thus smaller than the structure size of the respectively associated lens 15 the primary optics 24 , It is in 8A an embodiment with a constant pitch (distance between the centers of adjacent LEDs 4 ), ie a so-called pitch-preserving variant, and in 8B an embodiment in which different pitches occur, so a pitch-varying variant.

In 9 is again a modification of the embodiment according to 7A shown. Again, this is a primary optic 24 provided which a plurality of lenses 15 includes. In the illustrated embodiment, however, each LED 4 a plurality of lenses 15 assigned. The structure size of the LEDs 4 is thus larger than the structure size of the lenses 15 the primary optics 24 ,

In the 10A and 10B are various embodiments of optoelectronic chip-on-board modules 11 or sections of such chip-on-board modules 11 shown which in terms of an arrangement of the primary optics 24 relative to the LEDs 4 differ. In principle, for example, the embodiments may be otherwise according to the exemplary embodiment 7A correspond.

So shows 10A an embodiment in which an optical axis 27 a lens 15 and an optical axis 28 an LED 4 fall together, so, in a plan view of the chip-on-board module 11 , a lens center and a center of the LED 4 can lie one above the other. In 10B however, an embodiment is shown in which the optical axis 27 the lens and the optical axis 28 the LED 4 are shifted against each other. Another embodiment is possible, for example, a tilted configuration of the axes 27 . 28 ,

In 11 an embodiment is shown in which the optics 23 next to a primary optic 24 continue a secondary optics 25 having. This secondary optics 25 can turn one or more lenses or, as in 11 represented, one or more reflectors 26 include. For example, the embodiment according to one or more of 7A to 10B combined with one or more reflectors. In this case, one or more of the elements of secondary optics 25 one, several or all LEDs 4 be assigned.

In 12 is a modification of the embodiment according to 11 shown. Instead of a reflector, as in 11 illustrated, this embodiment shows that the secondary optics, alternatively or additionally, may also include one or more lenses.

In 13 is an example of a beam path within the embodiment according to 11 shown. From an LED 4 Exiting light initially passes the curved surface of this LED 4 associated lens 15 the primary optics 24 at which a refraction takes place, so that this surface as the actual optical element of the primary optics 24 acts. Then this is the primary optic 24 leaking light partly at the secondary optics 25 broken and / or collected and / or collimated. In the illustrated embodiment, in which an exemplary beam path is shown, by the primary optics 24 emerging rays on the surfaces of the reflector 26 the secondary optics 25 mirrored in the direction of a radiation direction 30 so that a usable solid angle range can be increased.

In 14 an embodiment is shown, which in turn is a combination of at least one primary optic 24 and at least one secondary optic 25 includes. In this embodiment, the secondary optics includes 25 but several elements, namely at least one reflector 26 and at least one lens 15 , While at primary optics 24 one LED each 4 a lens 15 is assigned, this exemplary embodiment shows by way of example, that a group of LEDs, in this case in each case 3 LEDs or more LEDs, a common secondary optics 25 may be assigned, such as a common reflector 26 and / or a common lens 15 , Again, different beam paths are indicated by way of example. It can be several units with a common secondary optics 25 be strung together in one or two spatial directions, as in 14 also shown as an example.

In the 15A and 15C different embodiments are shown, the different ways of realizing a surface of the optics 23 , in particular the silicone coating 12 , demonstrate. In the exemplary embodiments are examples of the realization of a surface structure of the primary optics 24 shown. Alternatively or additionally, however, surface structures of one or more optional secondary optics may also be used with the method according to the invention 25 be designed.

So is in 15A an embodiment shown, which essentially according to the embodiment according to 7A can correspond. In this case, a smooth surface texture of the lenses 15 intended. The lenses 15 can have a spherical appearance.

While in the embodiment according to 15A Exemplary identical elements of primary optics 24 , In particular, identical lenses are shown, the elements of the optics 23 within the optoelectronic module 11 also vary. This is exemplary in 15B shown. In this embodiment, the optic includes 23 a plurality of optical elements, in this case a plurality of lenses having different optical properties.

In 15C is finally shown that in 5 shown roughened surface structure 16 also with one or more optics 23 can be combined. By way of example, this is in the illustrated embodiment for a plurality of lenses 15 shown, which exemplarily here the primary optics 24 are assigned and which are exemplarily configured here analogous to the embodiment according to 15B , However, other embodiments are also possible in principle, for example, a roughened surface structure 16 in the embodiment according to 15A , Alternatively or in addition to a roughened surface structure 16 It is also possible to use other surface structuring, for example surface structuring in the form of Fresnel lenses.

LIST OF REFERENCE NUMBERS

1, 1 '

uncoated chip-on-board LED module

2, 2 '

carrier

3, 3 '

conductor path

4, 4 '

LED

5, 5 '

light cone

6

joint

7

overlap area

11-11 '' '

coated chip-on-board LED module

12

silicone coating

13

Coating of the carrier side surfaces

15

Silicone lens

16

roughened surface texture

17

phosphorescent material

18

Light of different wavelengths

20

mold

21

liquid silicone

22

silicone stock

23

optics

24

primary optics

25

secondary optics

26

reflector

27

optical axis lens

28

optical axis LED

30

radiation direction

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7638808 B2 [0003]
• US 20100065983 A1 [0003]
• US 20070045761 A1 [0003]
• US 7819550 B2 [0003]
• DE 102010044470 [0003]
• EP 1657758 A2 [0013, 0018]
• US 7638808 [0062]

Claims (17)

Method for coating an optoelectronic chip-on-board module ( 1 . 11 - 11 ''' ), which has a flat carrier ( 2 . 2 ' ) associated with one or more optoelectronic components ( 4 ), with a transparent, UV and temperature-resistant coating ( 12 ) of a silicone, characterized by the following process steps: a) casting a liquid silicone ( 21 . 22 ) in an upwardly open mold ( 20 ) having external dimensions corresponding to the external dimensions of the support ( 2 . 2 ' ) or exceed them, b) insertion of the support ( 2 . 2 ' ) in the form ( 20 ), wherein the optoelectronic component ( 4 ) or the optoelectronic components ( 4 ) completely into the silicone ( 21 ) and a surface of the carrier ( 2 . 2 ' ) the silicone ( 21 ) or the wearer ( 2 . 2 ' ) at least partially completely in the silicone ( 21 ), c) curing and crosslinking of the silicone ( 21 ) with the optoelectronic components ( 4 ) and the carrier ( 2 . 2 ' ), and d) removing the carrier ( 2 . 2 ' ) with the coating ( 12 ) from the cured silicone ( 21 ) out of form ( 20 ). A method according to claim 1, characterized in that the method steps a) and / or b) and / or c) and / or d) are carried out under an elevated atmospheric pressure, in particular at an atmospheric pressure between 4 and 10 bar, in particular between 5 and 7 bar. A method according to claim 1 or 2, characterized in that in the liquid silicone ( 21 . 22 ) optically functional materials ( 17 ), in particular phosphorescent and / or scattering materials or particles, are or are mixed. Method according to one of claims 1 to 3, characterized in that on a surface of the coating ( 12 ) a surface structure predetermined by the shape or later added ( 15 . 16 ) is produced. Method according to one of claims 1 to 4, characterized in that the carrier ( 2 . 2 ' ) to one or more edges with optoelectronic components ( 4 ) is or is equipped. Method according to one of claims 1 to 5, characterized in that the carrier ( 2 . 2 ' ) borderless and / or coated over the edge. Method according to one of the preceding claims, characterized in that the silicone ( 21 ) is shaped such that at least one optical component, in particular at least one lens ( 15 ), in which silicone ( 21 ) is formed. Method according to one of the preceding claims, wherein the method is carried out such that the chip-on-board module ( 1 . 11 - 11 ''' ) at least one of the at least one optoelectronic component ( 4 ) adjacent primary optics ( 24 ) and optionally at least one secondary optic ( 25 ), wherein at least one optic ( 23 ) selected from the group consisting of primary optics ( 24 ) and secondary optics ( 25 ) in the silicone ( 21 ) is formed. Opto-electronic chip-on-board module ( 11 - 11 ''' ), in particular producible according to a method according to one of the preceding claims, comprising a flat carrier ( 2 . 2 ' ) equipped with one or more optoelectronic components ( 4 ), with a transparent, UV and temperature-resistant coating ( 12 ) made of a silicone ( 21 . 22 ), characterized in that a surface of the carrier ( 2 . 2 ' ) with one or more optoelectronic components ( 4 ), borderless with the silicone ( 21 . 22 ) is coated. Opto-electronic chip-on-board module ( 11 - 11 ''' ) according to the preceding claim, characterized in that the carrier ( 2 . 2 ' ) on its side surfaces at least partially with the silicone ( 21 . 22 ) is coated. Opto-electronic chip-on-board module ( 11 - 11 ''' ) according to one of the preceding, an optoelectronic chip-on-board module ( 11 - 11 ''' ), characterized in that the silicone ( 21 . 22 ) an admixture of optically functional materials ( 17 ), in particular phosphorescent and / or scattering materials or particles. Opto-electronic chip-on-board module ( 11 - 11 ''' ) according to one of the preceding, an optoelectronic chip-on-board module ( 11 - 11 ''' ), characterized in that the coating ( 12 ) a surface structure ( 15 . 16 ), in particular lenses ( 15 ) or light-scattering roughenings ( 16 ). Opto-electronic chip-on-board module ( 11 - 11 ''' ) according to one of the preceding, an optoelectronic chip-on-board module ( 11 - 11 ''' ), characterized in that the coating ( 12 ) at least one optical component, in particular at least one lens ( 15 ) and / or at least one lens array. Opto-electronic chip-on-board module ( 11 - 11 ''' ) according to one of the preceding, an optoelectronic chip-on-board module ( 11 - 11 ''' ), characterized in that the chip-on-board module ( 11 - 11 ''' ) at least one of the at least one optoelectronic component ( 4 ) adjacent primary optics ( 24 ) and optionally at least one secondary optic ( 25 ), wherein at least one optic ( 23 ) selected from the group consisting of primary optics ( 24 ) and secondary optics ( 25 ) at least partially in the coating ( 12 ) is trained. Opto-electronic chip-on-board module ( 11 - 11 ''' ) according to one of the preceding, an optoelectronic chip-on-board module ( 11 - 11 ''' ), characterized in that the support ( 2 . 2 ' ) to an edge or to just before an edge with optoelectronic components ( 4 ) is equipped. Opto-electronic chip-on-board module ( 11 - 11 ''' ) according to one of the preceding, an optoelectronic chip-on-board module ( 11 - 11 ''' ), characterized in that it is produced or preparable by a method according to one of claims 1 to 6. System with two or more optoelectronic chip-on-board modules ( 11 - 11 ''' ) according to one of the preceding, an optoelectronic chip-on-board module ( 11 - 11 ''' ), characterized in that the supports ( 2 . 2 ' ) of the optoelectronic chip-on-board modules ( 11 - 11 ''' ) are arranged flush with each other or with a defined distance from each other next to each other, wherein in particular due to marginal placement of the carrier ( 2 . 2 ' ) with optoelectronic components ( 4 ) also across the borders between adjacent carriers ( 2 . 2 ' ) regular arrangement and spacing of optoelectronic components ( 4 ).

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