DE102015223143A1 - Lamp and method of manufacturing the lamp - Google Patents

Abstract

A lamp comprising an LED module (4) provided on a heat sink (2) and arranged in a housing (8) and covered with a lens (10) received on the housing (8), a cavity (20 ) is bounded by the heat sink (2) and / or the LED module (4) and the housing (8) and the lens (10) or cover. The LED module (4) is connected by means of multi-component injection molding in a mold with the heat sink (2). The lens (10) is sealingly connected to the housing (8) in the mold by means of a sealing compound (12) introduced by means of multicomponent injection molding. In one method of manufacturing the lamp, the lens (10) or cover (10) is sealed against the housing (8) in the mold in a single molding process.

Description

Technical area

The invention is based on a lamp, which are produced by means of a known injection molding technique, such as injection molding ("Injection Molding"), low pressure injection molding ("Low Pressure Injection Molding"), or multi-component injection molding ("In-Mold Manufacturing" or "In-Mold Assembly "), wherein the production of the lamp takes place in a sense in the mold.

Such lamps are, for example, used for vehicle lighting, so-called "LED retrofit lamps" and - used for general lighting, for example - so-called "LED retrofit downlights".

A light emitting diode (LED) may be in the form of at least one individually packaged light emitting diode or in the form of at least one LED chip. Alternatively or additionally, a plurality of LED chips may be mounted on a common substrate ("submount"). The at least one LED can be equipped with at least one own and / or common optics for beam guidance, e.g. at least one Fresnel lens, collimator, and so on. Instead of or in addition to inorganic LEDs, e.g. based on InGaN or AlInGaP, organic LEDs (OLEDs, for example polymer OLEDs) can generally also be used. Alternatively, the LED may be a laser diode or a laser diode array. The emission wavelengths of the LED can be in the ultraviolet, visible or infrared spectral range.

"Retrofit" lamps are lamps with a technically old or outdated base, in which a modern lamp vessel is added. In vehicle lighting, this may be, for example, a lamp with a base for a halogen lamp with a lamp vessel with an LED lamp to be able to use modern LED lamps in a vehicle that was originally equipped with connections for halogen lamps. As a "downlight" a lamp is referred to, the optics is designed for down beaming of light, for example, for use in a ceiling light, in particular a recessed ceiling light, by means of the room ceiling down a room is illuminated.

Producing such retrofit lamps, usually by means of in-mold manufacturing or multicomponent injection molding, involves particular difficulties, such as, for example, a connection of two plastic parts, in particular a substantially splash-tight connection of two plastic parts with a cavity enclosed therein, as occurs, for example, when connecting a LED Module or light engine of the lamp with a heat sink of the lamp is required and / or when connecting a lens or a cover of the lamp with a housing of the lamp.

In particular, the lens or cover plate is conventionally attached to the lamp housing by means of one of the aforementioned known injection molding methods, manual assembly and optionally manual rework, in order to meet the requirements of the essentially splash-proof connection. In this case, for example, for sealing a silicone adhesive is applied separately or alternatively a plastic part provided by means of a molded in a two-component casting method seal in particular of a thermoplastic elastomer. The lens or cover is then pressed by hand into the housing. The result is a blunt connection between the lens or cover and the housing, but which is a mechanical vulnerability and thus has a negative impact on a tightness of the substantially splash-tight connection.

State of the art

document WO 2008/141 630 A2 discloses a lamp cap for an electric lamp, which is manufactured by injection molding in several steps in different tools. With increased sealing requirements, the lamp cap can be placed in another tool to inject a sealing ring by means of a sealing material, wherein the sealing material passes through a connecting channel in a region of a contact tab portion of the lamp cap to seal there as well.

The change of the manufactured in each step teilfertig lamp base between the tools is complicated by the handling and the time required and possibly error prone, since the lamp base can be damaged when changing and / or there may be problems with the positioning of the lamp cap in each tool ,

Presentation of the invention

The object of the present invention is to provide a lamp with a substantially splash-proof connection of plastic parts with a cavity enclosed therein, which can be produced with reduced effort.

This object is achieved by a lamp according to the features of patent claim 1.

A further object of the present invention is to provide a method for producing a lamp having a substantially splash-tight connection of plastic parts with cavity enclosed therefrom with reduced expenditure.

This object is achieved by a manufacturing method according to the features of the independent method claim.

Particularly advantageous embodiments can be found in the dependent claims.

A lamp according to the invention has an LED module which is provided on a heat sink and is arranged in a housing and is covered with a lens or cover disc received on the housing, wherein a cavity of the heat sink and / or the LED module and the housing and the lens or cover is limited. The LED module is connected by means of multi-component injection molding in a mold with the heat sink. The lens or cover is sealingly connected by means of a multi-component injection molded sealing compound in the mold with the housing sealingly.

The use of multicomponent injection molding has the advantage that the lamp can be produced directly in the casting mold, which reduces handling steps, and / or a production time and thus production costs.

Advantageously, a, in particular circumferential, sealing lip or crimp seam is provided on the housing or on the lens or cover, by means of which the lens or cover is sealed against the housing in a closed state of the mold. Thus, overspray of the sealant in the cavity is avoidable.

In generic lamps of the housing and the lens or cover and the heat sink and / or the LED module, the cavity is limited, in particular included, which is why it is difficult to impossible, from the cavity from a counter force against overspraying of the sealant in the cavity applied.

Advantageously, the sealant is introduced by means of a low-pressure casting process in a joint between the lens or cover and the housing. Since a customary for low-pressure casting process pressure of about 2 to about 40 and a usual low-pressure casting cycle time of about 10 to 15 s between the corresponding values for classical injection molding and a two-component casting process, thus a nearly ideal compromise is found from a Using a low pressure casting process to avoid over-injection of the sealant into the cavity and short cycle times.

Alternatively, the sealant can be introduced by means of an injection molding process in the joint between the lens or cover and the housing / be.

The connecting joint is advantageously made thin, that is to say that a width of the connecting joint in relation to a length of the connecting joint is very small, for example in a ratio of 1 to 5, in particular 1 to 10, in particular 1 to 20.

In particular, the sealant is a thermoplastic elastomer or a hotmelt adhesive (hotmelt adhesive), which is advantageously or solvent-free. For example, the hot melt adhesive is a Technomelt material. Because of the use of the hotmelt adhesive, a filling pressure is reduced, which is required for introducing the sealant in the joint. Thus, in particular because of the applicability of the above-mentioned low-pressure casting method, the avoidance of the overspray of the sealant in the cavity further favors.

Advantageously, the thermoplastic elastomer or the hot melt adhesive is electrically insulating. Alternatively or additionally, the thermoplastic elastomer or the hot melt adhesive may be dyeable and / or printable. Alternatively or additionally, the thermoplastic elastomer or the hot melt adhesive may be UV-resistant and / or flame-retardant.

Advantageously, a, in particular in an axial direction of the lamp, extended flow path for the sealant between the lens or cover and the housing is provided. In particular, the connecting joint is formed such that a, in particular in the axial direction of the lamp, extended flow path for the sealant results. Although the elongated flow path causes a slight increase in the consumption of sealing compound, a significantly improved material flow in the connecting joint that is caused by this compensates for this small disadvantage by far. In addition, by this measure, the blunt formation of the weld line between the lens or cover and the housing and the consequent negative influence on the tightness thus avoided and increased cohesion in the weld line. As a result, by the formation of, in particular in the axial direction of the lamp, extended flow path for the Sealant in the joint ensures a substantially splash-tight connection of the lens or cover to the housing.

In particular, an injection pressure and / or a temperature of the sealant are adjusted such that the connecting joint is approximately completely filled by the sealant.

In particular, an injection opening for introducing the sealing compound into the connecting joint and an outlet opening for discharging the sealing compound from the connecting joint are arranged outside on the housing.

In particular, the injection opening and an outlet opening are arranged opposite one another on the housing. Thus, a uniform filling of the joint with the sealant is guaranteed.

In a method according to the invention for producing a lamp having an LED module which is provided on a heat sink and is arranged on a housing and is covered with a lens or cover disc received in the housing, wherein a cavity of the heat sink and / or is limited to the LED module and the housing and the lens or cover, a connection step is performed, in which the LED module is connected to the heat sink in a mold by means of multi-component injection molding. Furthermore, a sealing step is carried out in which the housing is sealingly connected to the lens or cover by means of a multi-component injection-molded sealant in the mold, wherein the sealing of the lens or cover against the housing in the mold in a single, in particular multi-stage, casting Process takes place.

An advantage of the method according to the invention is that the sealing step takes place in the same casting mold, as one or more or all of the manufacturing steps of the lamp, that is, in a single, in particular multi-stage, casting process.

In particular, the first semi-finished intermediate product is produced in the joining step.

Advantageously, a sealing lip, which is provided on the housing or on the lens or cover plate, applied by closing the mold so that the lens or cover is sealed against the housing. Thus, overspray of the sealant in the cavity is avoidable.

Advantageously, in a further step, the housing is connected to the heat sink in the mold by means of multi-component injection molding, in particular, the second semi-finished intermediate product is formed. In particular, the further step is a two-component casting and the housing is a first material component and the heat sink is a second material component.

The abovementioned production steps for the semi-finished intermediate products and / or the lamp according to the invention can be carried out simultaneously or successively.

For example, for manufacturing reasons, the first semi-finished intermediate or the second semi-finished intermediate product can be transferred from the mold to another mold, wherein the further mold is advantageously substantially identical to the mold and may differ especially in Angusseinrichtungen thereof. Thus, for example, only the housing can be potted with the heat sink in a manufacturing station and sealed in another manufacturing station, only the lens against the housing.

Brief description of the drawings

In the following, the invention will be explained in more detail with reference to an embodiment. The figures show:

1a a heat sink with LED module provided thereon of a lamp according to the invention in a three-dimensional view obliquely from above,

1b a cast on the heat sink with LED module housing of the lamp according to the invention in a three-dimensional view obliquely from above,

1c an inserted into the housing lens or cover of the lamp according to the invention in a three-dimensional view obliquely from above

2 a representation of a prototype of the lamp according to the invention in a three-dimensional sectional view obliquely from above,

3 an illustration of the lamp according to the invention with a connecting joint introduced sealing compound in a three-dimensional sectional view obliquely from above, and

4 a flowchart of a method according to the invention.

Preferred embodiment of the invention

1 shows various stages of manufacture of a lamp according to the invention 1 ,

In 1a is as a first semi-finished intermediate 1a a heat sink 2 with LED module provided 4 shown. The LED module 4 is as a framework 6 formed with a connector and in insert technology in the heat sink 2 inserted and connected by means of multi-component injection molding with it, in particular cast together in a mold, for example in a train with a production of the heat sink 2 , The frame 6 here is made of brass, can alternatively be made of copper or similar thermally conductive material. The heat sink 2 is here of a thermally conductive thermoplastic, for example, a graphite-added polyamide (PA).

1b shows as a second semi-finished intermediate 1b a housing 8th the lamp 1 Using multi-component injection molding with the heat sink 2 is connected, in particular so that is poured in the mold. The housing 8th is here of a thermoplastic material, in particular of a polycarbonate (PC).

The casting of the LED module 4 with the heat sink 2 may vary depending on the materials used together with a manufacture of the housing 8th and its encapsulation with the heat sink 2 in the mold in a two- or multi-component casting.

1c shows one in the housing 8th inserted lens 10 the lamp according to the invention 1 , The Lens 10 is by means of a sealant 12 against the case 8th sealed and connected. The Lens 10 is here from a thermoplastic material, in particular from a polycarbonate (PC), alternatively from a polymethylmethacrylate (PMMA).

The sealing takes place according to the invention in a single step, in particular together with or after the encapsulation of the LED module 4 with the heat sink 2 in the mold and / or together with or after the encapsulation of the housing 8th with the heat sink 2 in the mold.

The sealant 12 , here a thermoplastic elastomer or a hot melt adhesive ("hot melt adhesive" or "hot melt"), is on each outside of the housing 8th arranged injection port 14 and an outlet opening 16 (please refer 2 and 3 ) in a thin joint 18 einbringbar and / or from a thin joint 18 herausleitbar.

The thin connecting joint 18 is so between the lens 10 and the housing 8th formed in that one in an axial direction of the lamp 1 extended flow path for the sealant 12 in the joint 18 and a resulting improved material flow of the sealant 12 in the joint 18 results.

The injection opening 14 and the outlet opening 16 are opposite each other on the housing 8th arranged to give a uniform filling of the joint 18 with the sealant 12 to ensure.

In 2 is a prototype of the lamp according to the invention 1 shown schematically in section, in which it is easy to see how the joint 18 between a cover plate used as an alternative to the lens 10 and the housing 8th with the sealant 12 is filled.

From the cover 10 and the housing 8th is typically a cavity 20 included in the complete lamp 1 from the heat sink, not shown here 2 is limited. The LED module, not shown here 4 is in the cavity 20 arranged, but does not fill it. From the enclosed cavity 20 it is difficult, if not impossible, to apply a counterforce to overspraying of the sealant into the cavity.

Here as in 3 is the lamp 1 or the lens 10 or cover 10 already in against the case 8th sealed condition shown - a sealing lip on the lens 10 or cover 10 or on the housing 8th when closing the mold the lens 10 or cover 10 against the case 8th is therefore not shown here in the drawing.

The simplified injection port shown here 14 is in practice, as above 1c described and in 3 better to see, outside the case 8th arranged.

In 3 is an illustration of the lamp according to the invention 1 with the in the thin connecting joint 18 introduced sealing compound 12 shown in section. Clearly visible here are the opposite each other outside the housing 8th arranged injection port 14 and outlet opening 16 through which the sealant 12 in the joint 18 entry or exit. Because here is the heat sink 2 and the LED module 4 are shown, that of the housing 8th and the lens 10 enclosed and bounded by the heat sink cavity 20 clearly.

4 shows a flowchart of a method according to the invention with the following steps:
In a connection step 22 becomes the LED module 4 as an insert with the heat sink 2 connected in a mold by means of multi-component injection molding, it creates the first semi-finished intermediate product 1a ,

In a further step 24 becomes the first semi-finished intermediate 1a the housing 8th connected in the mold by means of multi-component injection molding, it creates the second semi-finished intermediate product 1b , Here is the case 8th a first material component and the heat sink a second material component, therefore the connection of the housing 8th and the heat sink 2 done in a two-component casting.

Next becomes a sealing step 26 carried out in which the second semi-finished intermediate 1b as an insert with the lens 10 as another insert by means of the introduced by means of multi-component injection molding sealant 12 is sealingly connected in the mold, with a seal of the lens 10 against the case 8th in the mold in a single step.

The above-mentioned manufacturing steps for the semi-finished intermediates 1a . 1b and / or the lamp according to the invention 1 can be performed simultaneously or sequentially.

For example, for manufacturing reasons, the first semi-finished intermediate 1a or the second semi-finished intermediate 1b be brought from the mold into another mold, wherein the further mold is advantageously largely identical to the mold and may differ especially in Angusseinrichtungen thereof. Thus, in a manufacturing station, for example, only the housing 8th with the heat sink 2 to be potted and in another manufacturing station only the lens 10 sealed against the housing.

Disclosed is a lamp with an LED module, which is connected by means of multi-component injection molding in a mold with a heat sink and a housing, in particular potted. Another manufacturing step of sealing a lens or cover plate for the LED module is executable in the mold by means of introducing a sealant into a joint between the lens or sealing disc and housing by means of multi-component injection molding. From the case usually arising cavity, which is enclosed by the lens or cover and the housing and limited by the heat sink, an application of a counter force that could prevent penetration of the sealant into the cavity, a so-called over-molding, difficult to impossible , An inventively provided on the housing or the lens or cover sealing lip which seals the lens or cover when closing the mold against the housing prevents the overspray of sealant in the cavity and on the one hand ensures a substantially splash-proof connection of lens or cover and housing and on the other hand, a proper function of the lamp. Thus, the lamp despite the enclosed cavity with the substantially splash-tight connection of the lens or cover and housing can be produced with reduced effort.

LIST OF REFERENCE NUMBERS

1

 lamp

2

 heatsink

4

 LED module

6

 frame

8th

 casing

10

 Lens / cover

12

 sealant

14

 Injection port

16

 outlet

18

 connecting joint

20

 cavity

22

 connecting step

24

 another step

26

 sealing step

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

• WO 2008/141630 A2 [0007]

Claims (15)

Lamp with a LED module ( 4 ) attached to a heat sink ( 2 ) and in a housing ( 8th ) is arranged and with a on the housing ( 8th ) received lens ( 10 ) or cover ( 10 ), wherein a cavity ( 20 ) from the heat sink ( 2 ) and / or the LED module and the housing ( 8th ) and the lens ( 10 ) or cover ( 10 ), and wherein the LED module ( 4 ) by means of multi-component injection molding in a mold with the heat sink ( 2 ), characterized in that the lens ( 10 ) or cover ( 10 ) by means of a multicomponent injection-molded sealing compound ( 12 ) in the mold with the housing ( 8th ) is sealingly connected. A lamp according to claim 1, wherein on the housing ( 8th ) or on the lens ( 10 ) or cover ( 10 ) a sealing lip is provided, by means of the closed state of the mold, the lens ( 10 ) or cover ( 10 ) against the housing ( 8th ) is sealed, to avoid overmolding of the sealant ( 12 ) in the cavity ( 20 ). Lamp according to claim 1 or 2, wherein the sealing compound ( 12 ) by means of an injection molding or low pressure casting process in a joint ( 18 ) between the lens ( 10 ) or cover ( 10 ) and the housing ( 8th ) is introduced. Lamp according to one of claims 1 to 3, wherein an extended flow path for the sealing compound ( 12 ) in the joint ( 18 ) is designed to improve a material flow of the sealant ( 12 ). Lamp according to one of claims 1 to 4, wherein the sealing compound ( 12 ) is a thermoplastic elastomer or a hot melt adhesive.  A lamp according to claim 5, wherein the thermoplastic elastomer or the hot melt adhesive is electrically insulating.  A lamp according to claim 4 or 5, wherein the thermoplastic elastomer or the hot melt adhesive is dyeable and / or printable.  Lamp according to one of claims 5 to 7, wherein the thermoplastic elastomer or the hot melt adhesive is formed UV-resistant and / or flame retardant and / or solvent-free. Lamp according to one of claims 3 to 8, wherein an injection pressure and / or a temperature of the sealant ( 12 ) are set such that the connecting joint ( 18 ) completely from the sealant ( 12 ) is filled out. Lamp according to one of claims 3 to 9, wherein an injection opening ( 14 ) for introducing the sealant ( 12 ) in the joint ( 18 ) and an outlet opening ( 16 ) for a discharge of the sealant ( 12 ) from the joint ( 18 ) on the outside of the housing ( 8th ) are arranged. Lamp according to claim 10, wherein the injection opening ( 14 ) and the outlet opening ( 16 ) opposite to each other on the housing ( 8th ) are arranged. Method for producing a lamp comprising an LED module ( 4 ), which on a heat sink ( 2 ) and in a housing ( 8th ) is arranged and with a on the housing ( 8th ) received lens ( 10 ) or cover ( 10 ), wherein a cavity ( 20 ) from the heat sink ( 2 ) and / or the LED module ( 4 ) and the housing ( 8th ) and the lens ( 10 ) or cover plate is limited, with a connecting step ( 22 ), in which the LED module ( 4 ) with the heat sink ( 2 ) in a mold by means of multi-component injection molding, characterized by a sealing step ( 26 ), in which the housing ( 8th ) with the lens ( 10 ) or cover ( 10 ) by means of a multicomponent injection-molded sealing compound ( 12 ) is sealingly connected in the mold, the sealing of the lens ( 10 ) or cover ( 10 ) against the housing ( 8th ) in the mold in a single casting process. The method of claim 12, wherein a sealing lip attached to the housing ( 8th ) or on the lens ( 10 ) or cover ( 10 ) is applied by closing the mold so that the lens ( 10 ) or cover ( 10 ) against the housing ( 8th ) is sealed, to avoid overspray the sealant ( 12 ) in the cavity ( 20 ). Method according to claim 12 or 13, wherein in a further step ( 24 ) the housing ( 8th ) with the heat sink ( 2 ) is connected in the mold by means of multi-component injection molding.  Method according to one of claims 12 to 14, wherein at least one or more or all of the steps for the manufacture of the lamp are carried out simultaneously or successively in the mold.

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