DE102013220674A1 - lighting device - Google Patents

Abstract

The invention relates to a lighting device. The lighting device comprises a reflective substrate having a mounting side, and an insulating layer disposed on the mounting side of the reflective substrate. The insulating layer has an opening with a circumferential side surface. The lighting device has a circumferential reflective cover in the region of an edge of the opening of the insulating layer, which covers the circumferential side surface of the opening. The lighting device has at least one semiconductor light source, which is arranged in an area surrounded by the reflective cover on the mounting side of the reflective substrate. The invention further relates to a method for producing a lighting device.

Description

The invention relates to a lighting device which has a reflective substrate and at least one semiconductor light source. The invention further relates to a method for producing a lighting device.

A lighting device may comprise a substrate with a mounting side and at least one mounted on the mounting side semiconductor light source for emitting a light radiation. The at least one semiconductor light source can be realized in the form of a light-emitting diode chip (LED, light-emitting diode).

One or more light-emitting diode chips with a radiation-transmissive chip substrate made of sapphire, in which a light output can also take place via the sapphire substrate, can be arranged directly on a highly reflective substrate in order to enable effective radiation reflection. Usually, an insulating layer is additionally arranged on the mounting side of the reflective substrate. On the insulating layer tracks are formed. The insulating layer ensures sufficient electrical insulation between the conductor track plane and the reflective substrate. The insulating layer has an opening, whereby a part of the mounting side of the reflective substrate is released. In this area, the at least one light-emitting semiconductor chip is arranged on the mounting side. The opening of the insulating layer may also serve as a cavity for receiving a phosphor-filled potting compound, so that a conversion of light radiation of the at least one semiconductor chip can be effected.

Conventionally, the insulating layer is formed of a white dielectric material. The dielectric used is usually a so-called BT material (bismaleimide triazines). However, such a material is relatively expensive. Another disadvantage is a relatively low reflectivity. During operation of the lighting device, it is therefore possible for absorption of light radiation to occur on an inner side surface of the opening of the insulating layer. This is associated with efficiency losses.

As part of the production, the insulating layer having the opening is laminated to the reflective substrate with the aid of an adhesive. In this process, it may happen that a part of the adhesive runs into the opening at the edge and in this area covers the mounting side of the reflective substrate. Influences such as temperature and UV exposure can cause yellowing of the adhesive that has run into it. This can lead to an additional absorption of light radiation. To avoid adhesive running into the opening, a high viscosity "low flow" adhesive can be used. This can only partially solve the problem of radiation absorption.

The object of the present invention is to provide a solution for an improved lighting device.

This object is solved by the features of the independent claims. Further advantageous embodiments of the invention are specified in the dependent claims.

According to one aspect of the invention, a lighting device is proposed. The lighting device comprises a reflective substrate having a mounting side, and an insulating layer disposed on the mounting side of the reflective substrate. The insulating layer has an opening with a circumferential side surface. The lighting device further comprises a circumferential reflective cover in the region of an edge of the opening of the insulating layer, which covers the circumferential side surface of the opening. The lighting device further comprises at least one semiconductor light source, which is arranged in an area surrounded by the reflective cover on the mounting side of the reflective substrate.

In the lighting device, absorption of light radiation at the inner side surface of the opening of the insulating layer can be prevented by the reflective cover formed in this region. The reflective cover may instead allow for effective radiation reflection. As a result, the lighting device can exhibit higher efficiency than a conventional lighting device. For example, an increase in efficiency of up to 2.5% is possible.

The use of the reflective cover for radiation reflection furthermore offers the possibility of forming the insulating layer from a material which is no longer necessarily white or has a certain reflectivity. The conventionally used BT material can therefore be replaced by a less expensive insulating material or dielectric.

For the lighting device, different embodiments may be considered, as will be described in more detail below.

The reflective cover may be electrically non-conductive or electrically insulating. In one possible embodiment, the reflective cover has a radiation-transmissive, electrically insulating base material and therein embedded reflective particles on. As a result, the cover can be highly reflective. The base material of the cover may be a temperature and / or UV-stable material, so that decomposition and yellowing with high reliability can be avoided. A base material with such properties is, for example, silicone. The reflective particles may be, for example, TiO ₂ particles.

The reflective substrate may be designed in a targeted manner for enabling effective radiation reflection in the area of the mounting side. In this sense, according to a further embodiment, it is provided that the reflective substrate has a mirror layer and a reflection-enhancing dielectric layer arranged on the mirror layer. The dielectric layer forms the mounting side of the reflective substrate. The mirror layer may, for example, be a metallic layer, for example a silver layer. The dielectric layer may be, for example, a layer system of oxides. The dielectric layer can simultaneously serve as a protective layer to prevent corrosion of the mirror layer. In addition to these layers, the reflective substrate may have a metallic carrier layer. The carrier layer may be, for example, an aluminum layer. The aforementioned layers may be in the form of a layer stack. Instead of the aforementioned materials, other materials may be used. It is possible, for example, for the mirror layer to be in the form of highly reflective ceramic, for example of Al 2 O 3.

The at least one semiconductor light source is located within the opening of the insulating layer and is enclosed by the reflective cover. The reflective cover, which may be spaced from the at least one semiconductor light source, has a closed circumferential structure. The shape of the reflective cover may depend on the shape of the opening of the insulating layer.

For example, it is possible for the opening of the insulating layer to have a circular contour in plan view. In this embodiment, the circumferential side surface of the opening may be a curved and completely circumferential surface. The reflective cover covering the side surface may have a circular ring shape in plan view in this embodiment.

Alternatively, the opening of the insulating layer in the plan view also have a different contour, for example a polygonal or rectangular contour. In this way, the circumferential side surface of several or four adjoining partial surfaces (side edges) composed. In this embodiment, the reflective cover covering the side surface can have, in plan view, a closed shape or frame shape corresponding to a polygon or rectangle, optionally with rounded corners.

In cross section, the reflective cover may have a hump-shaped structure. The covering of the edge of the opening of the insulating layer by the reflective cover may not be compliant, so that the reflective cover may have a variable, non-uniform thickness.

The reflective cover may be disposed within the opening on the reflective substrate or on the mounting side of the reflective substrate. Depending on the production of the lighting device, an adhesive may also be present in this area, which covers the mounting side of the reflective substrate. In this case, the reflective cover can cover the adhesive, so that a radiation absorption on the adhesive can be avoided.

The reflective cover may also be present outside the opening of the insulating layer. In such an embodiment, the reflective cover may be arranged in the region of the edge of the opening on a side of the insulating layer facing away from the mounting side. As a result, radiation absorption on the insulating layer can be avoided with high reliability.

In a further embodiment, the insulating layer and the reflective cover project beyond the at least one semiconductor light source. This refinement, which makes it possible to cast or fill in the region of the at least one semiconductor light source in the production of the lighting device, may be considered with regard to the embodiment described below.

In a further embodiment, the lighting device has a potting compound, from which the at least one semiconductor light source is enveloped. The potting compound may adjoin at least the at least one semiconductor light source, the mounting side of the reflective substrate, and the reflective cover. The potting compound, which may project beyond the at least one semiconductor light source and the insulating layer, may be a phosphor-filled potting compound. With the phosphor-filled potting compound, a conversion of light radiation of the at least one semiconductor light source can be effected.

The at least one semiconductor light source may be a light-emitting diode chip. The light-emitting diode chip can be a volume emitter and have a radiation-transmissive chip substrate, for example of sapphire. The radiation-transmissive chip substrate can form a rear side of the light-emitting diode chip. In the region of the front side, the light-emitting diode chip may have a semiconductor layer sequence with an active zone for generating radiation and two front side contacts. The light-emitting diode chip can be arranged with the radiation-transmissive chip substrate on the mounting side of the reflective substrate. A light emission can be done not only on the front side, but also on other sides or on the radiation-permeable chip substrate.

During operation of the lighting device, the at least one semiconductor light source can emit primary light radiation. In one embodiment of the lighting device with a phosphor-filled potting compound, the primary light radiation of the at least one semiconductor light source can be at least partially converted into one or more secondary light radiations. In this way, a mixed radiation can be generated. For example, the primary light radiation can be a blue light radiation, which is converted with the aid of the phosphor-filled potting compound into one or more light radiations in the green to red spectral range in order to produce a white mixed radiation. The mixed radiation can be delivered via the potting compound.

In the lighting device, a radiation component, which is emitted in the direction of the mounting side of the reflective substrate, may be reflected on the reflective substrate. A radiation component emitted in the direction of the insulating layer or in the direction of the side surface of the opening of the insulating layer can be reflected on the reflective cover. This results in the high efficiency of the lighting device. In one embodiment of the lighting device with a phosphor-filled potting compound each primary, scattered and converted radiation components can be reflected.

In a further embodiment, the lighting device has a frame arranged on the insulating layer. The frame may surround the reflective cover. Furthermore, the frame may be spaced from the reflective cover. The above-mentioned potting compound is disposed in an area enclosed by the frame. The frame can serve as a dam, and provide a lateral boundary at a performed in the manufacture of the lighting fixtures with the potting compound.

The frame may have the same material or material composition as the reflective cover. In this way, light radiation with high efficiency can be reflected on the frame.

It is also possible to use the reflective cover itself as a dam for providing a lateral boundary in a filling carried out in the manufacture of the lighting device with the potting compound, so that the use of an additional frame can be omitted. In this sense, it is provided according to a further embodiment that the reflective cover encloses a recess, within which the potting compound is arranged.

As stated above, the reflective cover enables a configuration of the insulating layer of a low-cost material. It may, for example, be considered to form the insulating layer from a cost-effective insulating base material used in the printed circuit board area, also referred to as prepreg material. The prepreg material may comprise a carrier material, for example in the form of a fabric, and a resin material. Possible carrier materials are, for example, paper and / or glass fiber fabric. Possible resin materials are, for example, epoxy resin or phenolic resin. The prepreg material may be, for example, an FR4, FR2 or CEM material.

In a further embodiment, the lighting device has conductor tracks arranged on the insulating layer. About the conductor tracks, the at least one semiconductor light source can be supplied with electrical energy. An electrical connection between the conductor tracks and the at least one semiconductor light source can be realized via bonding wires. In a possible embodiment of the lighting device with a plurality of semiconductor light sources, these can also be electrically connected to one another via bonding wires. The above-mentioned frame and / or the reflective cover may also be arranged in regions on the conductor tracks.

According to a further aspect of the invention, a method for producing a lighting device is proposed. The lighting device has the structure described above or a structure according to one or more of the above-mentioned embodiments. The method includes providing a reflective substrate with a mounting side and disposing an insulating layer on the mounting side of the reflective substrate. The insulating layer has an opening with a circumferential side surface. The method further comprises forming a circumferential one reflective cover in the region of an edge of the opening of the insulating layer, which covers the circumferential side surface of the opening. The method further comprises arranging at least one semiconductor light source on the mounting side of the reflective substrate.

The lighting device formed in this way is characterized by a high efficiency. During operation of the lighting device, light radiation can be reflected with high efficiency on the mounting side of the reflective substrate and on the reflective edge cover. Furthermore, the insulating layer may be formed from a low-cost material or a low-cost material composition.

In one possible embodiment of the method, forming the reflective cover comprises performing a dosing process. In this case, a material forming the cover can be applied with high accuracy in the region of the edge of the opening. In the metering process, for example, a needle dispenser can be used.

In another embodiment, forming the reflective cover includes performing a printing process. As a result, the cover can also be formed with high accuracy in the region of the edge of the opening. The printing process may be carried out, for example, by means of a suitable printing device which ejects droplets of a material forming the cover (jetting). It is also possible to perform printing using a suitable printing form. Here, a stencil printing form or a screen printing form can be used.

In addition to the above steps, the method may include further steps. This includes, for example, forming a potting compound surrounding the at least one semiconductor light source. Previously, a frame enclosing the reflective cover can be formed on the insulating layer, which can serve as a lateral boundary for filling with the potting compound. It is possible to form the reflective cover and the frame in a common process (for example, dosing or printing), or also in succession. Alternatively, the formation of the frame may be omitted, and the reflective cover itself may be used to provide a lateral boundary.

The insulating layer may be provided with traces on one side of the insulating layer. In this regard, another possible step of the method is a wire bonding process in which the at least one semiconductor light source is connected to the traces. In the case of a plurality of semiconductor light sources, these can likewise be electrically connected to one another in the wire bonding process.

The formation of the reflective cover may be performed, for example, prior to arranging the at least one semiconductor light source on the mounting side of the reflective substrate. The formation of the reflective cover can also take place after and before the wire bonding process or after the wire bonding process.

The steps of the method may be performed in a suitable order. Considered, for example, the procedure described below.

The insulating layer may be provided with the opening and conductive traces on one side of the insulating layer, and disposed on the reflective substrate in a lamination process. After the lamination process, the reflective cover may be formed in the region of the edge of the opening of the insulating layer. Following this, the at least one semiconductor light source can be arranged on the mounting side of the reflective substrate, and connected to the conductor tracks in a subsequent wire bonding process. In the case of a plurality of semiconductor light sources, these can be electrically connected to one another in the wire bonding process. Following this, the formation of the potting compound can take place. For this purpose, the frame can first be produced on the insulating layer.

In an alternative methodology, the formation of the reflective cover may be performed after arranging the at least one semiconductor light source on the mounting side of the reflective substrate and before performing the wire bonding process. In another possible process flow, the formation of the reflective cover may be performed after arranging the at least one semiconductor light source on the mounting side of the reflective substrate and after performing the wire bonding process. This variant can be considered, for example, if the reflective cover serves at the same time as a dam to provide a lateral boundary for filling with the potting compound.

Furthermore, with regard to the manufacturing method, it is possible to produce a plurality of lighting devices in a parallel manner. Here, an insulating layer with a plurality of openings for the individual lighting devices may be provided and on the reflective substrate to be ordered. This can be followed by further manufacturing steps to produce a coherent composite of several lighting devices. Among others, a reflective cover may be formed in each case in the region of the edge of the individual openings of the insulating layer, and inside each opening at least one semiconductor light source may be arranged on the mounting side of the reflective substrate. After completing the lighting devices, the coherent composite can be separated into separate lighting devices.

It should be noted that features and details mentioned above with respect to the lighting device can also be used in the manufacturing process.

The above-explained and / or reproduced in the dependent claims advantageous embodiments and refinements of the invention can - except for example in cases of clear dependencies or incompatible alternatives - individually or in any combination with each other are used.

The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of exemplary embodiments, which are explained in more detail in connection with the schematic drawings. Show it:

1 an illustration of a lighting device comprising a reflective substrate, an insulating layer having an opening, a reflective cover in the region of an edge of the opening of the insulating layer, a plurality of semiconductor light sources, a frame and a potting compound;

2 a representation of realized in the form of a layer stack reflective substrate;

3 a representation of a further lighting device, which in contrast to the lighting device of 1 has no frame; and

4 a representation of measurement results to illustrate an increase in efficiency through the use of a reflective cover.

On the basis of the following schematic figures, embodiments of lighting devices 100 . 101 with semiconductor light sources 150 and related manufacturing processes. Here, processes can be carried out, which are known from the production of light-emitting devices and from semiconductor technology. Furthermore, common materials can be used in these areas. Therefore, this is only partially discussed below. It is further noted that the figures are merely schematic in nature and are not to scale. In this sense, components and structures shown in the figures may be exaggerated or oversized for clarity.

1 shows a schematic side view of a lighting device 100 , The lighting device 100 has a reflective substrate 110 on, which has a high reflectivity. On a in 1 upward facing front 115 of the substrate 110 are other components of the lighting device 100 arranged. This page is hereafter as a mounting page 115 designated.

The highly reflective substrate 110 is designed such that in the area of the mounting side 115 An effective reflection of light radiation can be caused. For this purpose, the substrate 110 in the form of a layer stack of superimposed layers 111 . 112 . 113 realized, whose construction in 2 is shown.

The reflective substrate 110 has a metallic carrier layer 111 made of, for example, aluminum, a metallic mirror layer 112 made of, for example, silver and a dielectric layer 113 on. The dielectric layer 113 showing the mounting side 115 of the substrate 110 forms, serves to reflection enhancement and protection of the mirror layer 112 from corrosion. The dielectric layer 113 may comprise a layer system of oxides. The radiation reflection can with a high effectiveness over in the area of the mounting side 115 of the substrate 110 present mirror layer 112 in interaction with the dielectric layer 113 be caused. In addition to the in 2 shown layers 111 . 112 . 113 can the substrate 110 Further, an adhesive layer, not shown, between the carrier layer 111 and the mirror layer 112 exhibit.

The lighting device 100 from 1 has different components on the mounting side 115 of the reflective substrate 110 on. One of these components is one on the mounting side 115 arranged insulating layer 120 , The insulating layer 120 is used to carry printed conductors 130 used. The tracks 130 , which may be formed of copper, are on one of the mounting side 115 of the substrate 110 opposite side or front of the insulating layer 120 arranged. The insulating layer 120 makes for a sufficient electrical insulation between the tracks 130 and the substrate 110 ,

The insulating layer 120 has an opening 121 with an inner circumferential side surface 122 on. In cross section, the side surface 122 or can side flanks thereof perpendicular to the mounting side 115 the reflective substrate, as in 1 is shown. The opening 121 the insulating layer 120 For example, in plan view, it may have a circular contour (not shown). In this embodiment, the side surface 122 the insulating layer 120 a curved and completely circumferential surface.

Another component of the lighting device 100 from 1 is an electrically non-conductive reflective cover 140 , which are in the area of the edge of the opening 121 the insulating layer 120 is trained. The cover 140 has a circumferential closed shape and covers the entire circumferential side surface 122 the opening 121 the insulating layer 120 , In the event that the opening 121 the insulating layer 120 in the plan view as described above is circular, the cover 140 have a circular ring shape in the plan (not shown).

In cross section, which has the edge region of the opening 121 enveloping cover 140 a hump-shaped or hill-shaped structure. As in 1 shown has the cover 140 a variable, uneven thickness. This covers the cover 140 at the edge of the opening 121 a part of the mounting side 115 of the reflective substrate 110 , The cover 140 also extends partially outside the opening 121 , and covered at the edge of the opening 121 a part of the front side of the insulating layer 120 ,

The reflective cover 140 serves to, in the area of the edge of the opening 121 the insulating layer 120 to allow effective reflection of light radiation, so that a radiation absorption at the insulating layer 120 is avoided. The cover 140 points to this purpose, as in 1 is indicated, a radiolucent base material 142 and in the basic material 142 embedded reflective particles 143 on. That way, the cover can 140 be highly reflective. At the base material 142 For example, it can be silicone. Such a material is characterized by a high temperature stability and UV resistance. With the reflective particles 143 they may be, for example, TiO ₂ particles.

The insulating layer 120 Can with the help of an adhesive on the mounting side 115 of the reflective substrate 110 be attached. In the course of applying the insulating layer 120 on the substrate 110 It may happen that some of the adhesive in the from the opening 121 the insulating layer 120 enclosed area runs into it. This can be a part of the mounting side 115 of the substrate 110 inside the opening 121 covered with the adhesive (not shown). The embedded adhesive may be from the reflective cover present in this area 140 be covered, so that a radiation absorption on the adhesive can be avoided.

The use of the reflective edge cover 140 makes possible the insulating layer 120 from a dielectric material, which is not necessarily reflective. The insulating layer 120 may be formed, for example, from a cost-effective and used in the PCB area insulating prepreg material. Such a material may comprise a carrier material, for example in the form of a fabric carrier, and a resin material. Possible carrier materials are, for example, paper and / or glass fiber fabric. Possible resin materials are, for example, epoxy resin or phenolic resin. The usable prepreg material may be, for example, an FR4, FR2 or CEM material.

In 1 is illustrated that the reflective cover 140 on the front of the insulating layer 120 to the tracks 130 but not covered. However, it is also possible that the cover 140 not up to the tracks 130 extends, or that the cover 140 one or more tracks 130 covered in places. The second variant may be present, for example, if the interconnects 130 deviating from 1 closer to the edge or to the edge of the opening 121 the insulating layer 120 come close.

The lighting device 100 from 1 furthermore has several, on the mounting side 115 of the reflective substrate 110 arranged optoelectronic semiconductor chips 150 on. The semiconductor chips 150 are designed to generate a light radiation. The semiconductor chips 150 are inside the opening 121 the insulating layer 120 and within one of the reflective cover 140 surrounded area. The semiconductor chips 150 are spaced from the cover 140 , The insulating layer 120 and the reflective cover 140 overhang the semiconductor chips 150 , This is related to a front light exit direction of the semiconductor chips 150 ,

In the light-emitting semiconductor chips 150 these can be, in particular, light-emitting diode chips. The semiconductor chips 150 may be made in a conventional manner, and not shown Components such as a radiation-transparent chip substrate, such as sapphire have. In this embodiment, the semiconductor chips 150 with the radiation-transmissive chip substrate on the reflective substrate 110 be arranged. Front side, the semiconductor chips 150 a arranged on the chip substrate semiconductor layer sequence having an active zone for generating radiation. Furthermore, the semiconductor chips 150 have two front side contacts. In operation, the semiconductor chips 150 emit light radiation over the front side and over other sides or over the radiation-permeable chip substrate.

The semiconductor chips 150 are like in 1 shown via bonding wires 155 , which are connected to the front side contacts of the semiconductor chips 150 are connected, electrically connected. For example, there may be a series connection, a parallel connection, or a combined parallel and series connection. Semiconductor chips 150 at the edge of the chip arrangement or their front side contacts are also via bonding wires 155 to the tracks 130 connected. The tracks 130 can be suitable contact points or contact surfaces for connecting the bonding wires 155 exhibit.

Another component of the lighting device 100 from 1 is one on the insulating layer 120 and on the tracks here 130 arranged frame 149 , The frame 149 , which has a circumferential closed shape and the reflective cover 140 surrounds, may be spaced from the cover 140 be. For a circular contour of the opening 121 the insulating layer 120 can the frame 149 , comparable to the cover 140 , in the supervision have a circular ring shape. Furthermore, the frame 149 have the same material composition as the cover 140 , and therefore also from the base material 142 and the reflective particles contained therein 143 be formed (not shown).

In one of the frame 149 enclosed area is a potting compound 160 arranged, which is another component of the lighting device 100 from 1 is. The semiconductor chips 150 and the bonding wires 155 are from the potting compound 160 envelops. The side of the frame 149 adjacent potting compound 160 covers the reflective cover 140 , the mounting side 115 of the reflective substrate 110 in areas next to and between the semiconductor chips 150 , and the insulating layer 120 and the tracks 130 in an area between the cover 140 and the frame 149 , The frame 149 is used to dam as a lateral boundary at one in the manufacture of the lighting device 100 carried out applying the potting compound 160 provide.

At the potting compound 160 which the semiconductor chips 150 and the insulating layer 120 surmounted, it is a fluorescent filled potting compound 160 , In this way, a conversion of light radiation of the semiconductor chips 150 be effected. The potting compound 160 may comprise a radiation-transmissive base material, again, for example, silicone, and phosphor particles contained therein (not shown).

During operation of the lighting device 100 become the semiconductor chips 150 over the tracks 130 and bonding wires 155 supplied with electrical energy, causing the semiconductor chips 150 emit a primary light radiation. The primary light radiation can via the fluorescent filled potting compound 160 at least partially converted into one or more secondary light radiations. In this way, a mixed radiation can be generated, which the lighting device 100 about the potting compound 160 can radiate. It is possible, for example, that the semiconductor chips 150 emit a blue primary light radiation, which is converted into one or more secondary light radiation in the green to red spectral range, so that a white mixed radiation is generated.

The reflective substrate 110 can ensure that primary, scattered and converted radiation components, which are directed towards the mounting side 115 be radiated here, with a high degree of effectiveness reflected here. The reflective cover 140 can ensure that a radiation absorption in the area of the edge of the opening 121 the insulating layer 120 is avoided and instead radiated in the direction of this range radiation components are effectively reflected. Also on the frame 149 can be caused an effective radiation reflection. The lighting device 100 As a result, it can be characterized by high efficiency.

The following is a possible manufacturing method for manufacturing the lighting device 100 described. In the method, the insulating layer 120 with the opening 121 and the conductor tracks arranged thereon 130 provided, and in a lamination process on the mounting side 115 of the reflective substrate 110 arranged. Performing the lamination process may result in the traces 130 partly in the insulating layer 120 sink in and thus differ from the illustration in 1 not opposite the front of the insulating layer 120 can stand out.

Subsequently or after a cooling of the insulating layer 120 becomes the reflective edge cover 140 in the area of the edge of the opening 121 the insulating layer 120 educated. For this purpose, for example, a Dispense- or Dosierverfahren be performed, in which the base material 142 with the reflective particles contained therein 143 in the area of the edge of the opening 121 on the reflective substrate 110 and the insulating layer 120 is applied. Such a method, in which, for example, a needle dispenser can be used, can be carried out with high accuracy.

This advantage applies equally to another possible method in which the formation of the reflective cover 140 done by printing. In this case, a suitable printing device can be used, which are droplets of the base material 142 with the particles contained therein 143 ejects (jetting). It is also possible to perform printing using a suitable printing form. This can be a stencil printing form, in particular a special 3D stencil. Alternatively, a screen printing form can also be used.

Subsequently or after curing of the insulating cover 140 become the semiconductor chips 150 inside the opening 121 the insulating layer 120 and inside of the reflective cover 140 surrounded area on the mounting side 115 of the substrate 110 arranged. An attachment of the semiconductor chips 150 For example, it can be done with the aid of an adhesive, for example silicone glue. Subsequently, a Drahtbondprozess is performed, in which the bonding wires 155 to the chip contacts and tracks 130 be connected.

This will be followed by the frame 149 on the insulating layer 120 and the tracks 130 trained, which is comparable to the cover 140 may comprise performing a dosing or printing process. The frame 149 may differ from 1 Also be made such that to the interconnects 130 connected bonding wires 155 partly through the frame 149 extend through. Subsequently or after hardening of the frame 149 gets the whole of the frame 149 enclosed area with the potting compound 160 , for example, by pouring, filled. In this process, the frame is used 149 as a lateral boundary for the potting compound 160 , After curing of the potting compound 160 is the lighting device 100 finished.

It is possible to have several of the 1 shown lighting devices 100 in a parallel manner in the form of a coherent composite. Here, the provided insulating layer 120 several openings 121 on, and will the in 1 shown construction in a corresponding manner several times and in a common plane distributed on the reflective substrate 110 realized. Subsequently, the composite in separate lighting devices 100 to be isolated.

3 shows a further lighting device 101 , which essentially the same components and the same structure as the lighting device described above 100 having. Matching features and processes as well as identical and equivalent components will therefore not be described again in detail below. For details, reference is made to the above description instead.

The lighting device 101 from 3 has, in contrast to the above-described lighting device 100 no frame 149 on. Instead, it serves the area near the edge of the opening 121 the insulating layer 120 arranged and the circumferential side surface 122 the opening 121 covering reflective cover 140 even as a framework for providing a lateral boundary. The cover 140 can be formed for this purpose with a greater thickness or height and width, and in particular further outward over the insulating layer 120 extend, as can be seen from a comparison of 1 and 3 results. The reflective cover 140 encloses a recess serving as a cavity, within which the phosphor-filled potting compound 160 is arranged.

At the lighting device 101 from 3 are the tracks 130 also partially from the reflective cover 140 covered. Furthermore, they extend to the tracks 130 connected bonding wires 155 partly through the cover 140 therethrough.

The following is a possible manufacturing method for manufacturing the lighting device 101 described. Here, the insulating layer 120 with the opening 121 and the conductor tracks arranged thereon 130 provided, and in a lamination process on the mounting side 115 of the reflective substrate 110 arranged. The following are the semiconductor chips 150 on the mounting side 115 of the reflective substrate 110 and the wire bonding process is performed. Subsequently, the reflective cover 140 in the area of the edge of the opening 121 the insulating layer 120 trained, which can be done by means of a dosing or printing process. In this way are the to the tracks 130 connected bonding wires 155 partly from the cover 140 envelops. Following this will be the entire from the cover 140 enclosed area with the potting compound 160 filled. In this process, the cover is used 140 as a lateral boundary for the potting compound 160 ,

The use of the reflective cover 140 in the area of the edge of the opening 121 the insulating layer 120 as with the lighting devices 100 . 101 of the 1 . 3 the case allows an increase in efficiency over a conventional lighting device without such edge wrapping. To illustrate this advantage shows 4 the determined by light measurements relative luminous flux F of conventional lighting devices, which is normalized to the luminous flux of a lighting device with reflective cover. The measurements refer to a color temperature of 3000K.

The measurement results 181 . 182 refer to two conventional light emitting devices in which the circumferential side surface of an opening of an insulating layer is not covered and an adhesive used for fixing the insulating layer on a reflective substrate has leaked to the reflective substrate within the opening. Compared to the reflective cover lighting device, there is less luminous flux in the range of 2.5%. In other words, the use of the reflective cover allows an increase in efficiency of 2.5%

The other two results 191 . 192 relate to a further light measurement of the two conventional light-emitting devices, wherein previously the leaked within the opening adhesive has been removed. As a result, the lighting devices have a higher luminous flux, which, however, continues to be smaller than the luminous flux of the luminous device with reflective edge cover. Because due to the removal of the adhesive, no radiation absorption takes place on the adhesive. However, radiation absorption continues to occur in the area of the uncovered side surface of the opening of the insulating layer.

The embodiments explained with reference to the figures represent preferred or exemplary embodiments of the invention. In addition to the described and illustrated embodiments, further embodiments are conceivable which may include further modifications and / or combinations of features. For example, it is possible to use other materials instead of the above materials. For example, the mirror layer 112 a highly reflective ceramic layer, for example of Al 2 O 3. Furthermore, the above information on colors of light radiation and the above figures can be replaced by other information.

In a further modification, the insulating layer 120 a multi-sided or quadrangular opening in the supervision 121 exhibit. This also allows the reflective cover 140 in the supervision of a multi-or quadrangular shape, possibly with rounded corners have.

In a further possible modification, a lighting device with only a single semiconductor chip 150 on the mounting side 115 of the reflective substrate 110 be realized.

Furthermore, attention is drawn to the possibility of carrying out the manufacturing processes described above, if necessary in a different order. In this regard, it is conceivable, for example, in the lighting device 100 from 1 the reflective edge cover 140 only after arranging the semiconductor chips 150 on the mounting side 115 of the reflective substrate 110 and form before performing the wire bonding process. The edge cover 140 may be formed, for example, by printing using a suitable printing form, for example a stencil or screen printing form.

While the invention has been further illustrated and described in detail by way of preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

100, 101

lighting device

110

substratum

111

backing

112

mirror layer

113

Dielectric layer

115

mounting side

120

Insulating layer

121

opening

122

side surface

130

conductor path

140

Reflective cover

142

base material

143

particle

149

frame

150

Semiconductor chip

155

bonding wire

160

potting compound

181, 182

measurement result

191, 192

measurement result

F

Relative luminous flux

Claims (10)

Lighting device ( 100 . 101 ), comprising: a reflective substrate ( 110 ) with a mounting side ( 115 ); one on the mounting side ( 115 ) of the reflective substrate ( 110 ) insulating layer ( 120 ), having an opening ( 121 ) with a circumferential side surface ( 122 ); a circumferential reflective cover ( 140 ) in the region of an edge of the opening ( 121 ) of the insulating layer ( 120 ), which the circumferential side surface ( 122 ) of the opening ( 121 ) covers; and at least one semiconductor light source ( 150 ), which in one of the reflective cover ( 140 ) area on the mounting side ( 115 ) of the reflective substrate ( 110 ) is arranged. Lighting device according to claim 1, wherein the reflective cover ( 140 ) a basic material ( 142 ), in particular silicone, and embedded therein reflective particles ( 143 ) having. Lighting device according to one of the preceding claims, wherein the reflective substrate ( 110 ) a mirror layer ( 112 ) and one the mounting side ( 115 ) forming dielectric layer ( 113 ) for reflection enhancement. Lighting device according to one of the preceding claims, wherein the insulating layer ( 120 ) and the reflective cover ( 140 ) the at least one semiconductor light source ( 150 ). Lighting device according to one of the preceding claims, further comprising a potting compound ( 160 ), from which the at least one semiconductor light source ( 150 ) is wrapped. Lighting device according to claim 5, further comprising one on the insulating layer ( 120 ) ( 149 ), the casting compound ( 160 ) in one of the frames ( 149 ) enclosed area is arranged. Lighting device according to claim 5, wherein the reflective cover ( 140 ) encloses a recess, within which the potting compound ( 160 ) is arranged. Lighting device according to one of the preceding claims, wherein the insulating layer ( 120 ) is formed from a prepreg material. Method for producing a lighting device ( 100 . 101 ) according to one of the preceding claims, comprising the method steps: providing a reflective substrate ( 110 ) with a mounting side ( 115 ); Placing an insulating layer ( 120 ) on the mounting side ( 115 ) of the reflective substrate ( 110 ), which has an opening ( 121 ) with a circumferential side surface ( 122 ) having; Forming a circumferential reflective cover ( 140 ) in the region of an edge of the opening ( 121 ) of the insulating layer ( 120 ), which the circumferential side surface ( 122 ) of the opening ( 121 ) covers; and arranging at least one semiconductor light source ( 150 ) on the mounting side ( 115 ) of the reflective substrate ( 110 ). The method of claim 9, wherein forming the reflective cover (10). 140 ) comprises performing a dosing process or performing a printing process.

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