EP2505906B1 - Method for producing a lighting body on an LED basis - Google Patents

Description

The invention relates to a method for producing a lighting fixture based on LEDs, in particular as a light source replacement for a fluorescent lamp.

In practice, in particular fluorescent lamps are used for lighting purposes in addition to conventional incandescent lamps, which are also referred to as fluorescent tubes. They work on the principle of the gas discharge lamp and are usually distinguished from simple light bulbs by a higher economic efficiency. The dimensions of such fluorescent tubes are standardized. Fluorescent tubes are usually offered in different lengths. Basically, fluorescent lamps are characterized by a relatively long life. However, this is significantly reduced with frequent switching operations.

It has therefore already been proposed to replace conventional fluorescent lamps with LED-based lamps.

That's how it describes US 2007/0223225 A1 an LED-based luminaire as a replacement for a conventional fluorescent lamp, wherein a plurality of light-emitting diodes are mounted in a tubular body. This tubular body with the LEDs arranged therein should then be usable in a conventional lamp socket of a fluorescent lamp. However, the production of such a lighting fixture is relatively expensive.

The same applies to one from the DE 200 13 605 U1 known elongated light source in which light emitting diodes are arranged as light sources in the light source, side by side on longitudinal axes and each forming a chain on its own axis

EP 0 760 448 A2 discloses a method according to the preamble of claim 1.

Incidentally, it is known from practice to produce light emitting diode bands or LED function bands. Such LED functional bands usually consist of a flexible carrier tape on which a plurality of light-emitting diodes and further electronic components are arranged. Such light-emitting diode bands can be separated at discrete locations, so that then the desired contacting can take place. In the DE 20 2009 002 127 U1 It is proposed to produce an LED luminaire based on such an LED functional band, which has a housing in which the LED function band is arranged. The housing is filled with a transparent potting compound, so that the LED function band is embedded in the potting compound. In addition, the housing can be filled with a second, opaque potting compound, which forms a housing cover. As a result, a particularly uniform illumination is achieved and the previously occurring by a plurality of LEDs dot effect can be avoided. This LED luminaire should also be used as a replacement for existing fluorescent tube luminaires. However, the production of the lamp is also relatively expensive.

Finally, that describes DE 10 2009 052 697 A1 a lighting device based on LED, wherein on the LEDs containing the lighting fixture end terminal adapter are plugged so that the lamp should be used in conventional fluorescent lamp sockets.

Overall, it is therefore anxious to replace conventional fluorescent lamps with LED solutions. The preparation of the proposed solutions, however, is relatively expensive, so that this technique has so far found little input into practice. - This is where the invention starts.

The invention has for its object to provide a simple and economical method for producing a lighting fixture based on LEDs, in particular LED lighting fixtures are to be produced, which can be used as a lamp replacement for conventional fluorescent lamps.

To solve this problem, the invention teaches a method for producing a lighting fixture based on LED, in particular as a lamp replacement for a fluorescent lamp, wherein a populated with a plurality of LEDs LED function band in an extrusion device continuously to form an LED strip in at least one thermoplastic Plastic is embedded, wherein the LED strip is then divided into several LED strips of predetermined length and wherein one or more terminal adapters are attached to one or both ends of an LED strip.

Equipped LED function band means a carrier tape which z. B. at predetermined intervals with a plurality of light emitting diodes (LEDs) is equipped and which is also equipped with running in the longitudinal direction of the carrier strip traces and beyond with electrical or electronic components, which are required in the usual way for the operation of the LEDs. Such LED functional bands are basically known in practice, they are usually operated with a supply voltage of 12 V or 24 V (DC). Such LED functional bands are embedded in at least one thermoplastic by extrusion.

The invention is initially based on the recognition that, as it were, "endless" LED tapes can be produced continuously by means of plastic extrusion, wherein basically conventional LED functional tapes are embedded in at least one thermoplastic material in the course of the extrusion become. From such "endless" LED strips can now easily produce lighting fixtures that can serve as a luminaire replacement for a fluorescent lamp by the LED strip is divided into a plurality of LED strips in a predetermined length. The LED strips produced in this way can easily be provided with connection adapters, so that the LED strips thus produced with the adapters can easily be used as a lighting fixture. In particular, it is not necessary to mount individual LEDs or LED strips in a housing. It is also not necessary to pour light-emitting diodes or sections of LED functional bands consuming into individual housing components. The production of the LED strips is carried out continuously in the way of plastic extrusion and the subsequently cut strips can be used without further costly assembly, only after mounting the required connection adapter, readily as a lighting fixture. Production by means of extrusion is particularly economical, so that the desired lighting fixtures can be produced relatively inexpensively. The LED function bands forming the starting point can be produced endlessly in advance with a desired assembly and distribution, that is to say the so-called "piercing points" are set up so that LED strips of the desired length can be produced. As a result, it is also possible to produce lighting fixtures of various lengths, so that a simple adaptation to the required geometry can take place in the course of production. Taking into account the fact that conventional fluorescent lamps are offered in very specific lengths for very specific lamp holders so can be in this way LED lighting fixture as a replacement in exactly the same lengths, z. As for conventional versions, manufacture. Double-capped fluorescent lamps have hitherto been covered by the DIN EN60081 standard and single-capped fluorescent lamps of the DIN EN60901 standard. It is therefore within the scope of the invention, the lighting fixture with the proviso that the standard there fluorescent lamps are readily replaced, so that the lighting fixtures according to the invention can thus be mounted in pedestals or sockets, which are designed for the fluorescent lamps described in these standards. Thus, fluorescent lamps can be replaced on a large scale without costly retooling. This is especially important if z. B. in the commercial sector fluorescent lamps are mounted on a large scale, z. As for the illumination of halls, workshops, etc .. It is therefore not necessary to replace the lamp holders. Rather, it is within the scope of the invention to provide lighting fixtures, which can be used directly in such lamp holders without further adaptation. This succeeds z. For example, when the mounted on the LED strip connection adapter are equipped with the required electrical or electronic, so that the LED lighting fixture is operated with conventional ballasts of the fluorescent lamp. This can be realized, for example, by integrating transformers in the connection adapters, which convert the mains voltage into suitable DC voltage of, for example, 10 V DC. B. Transform 12V or 24V.

However, it is also within the scope of the invention that while recourse is made to conventional lamp sockets, they are modified in a particular way to mount therein the LED lighting fixture. So it is conceivable that the lamp holder is used, but that parts of the electrical system or electronics, for. B. the ballast be replaced or removed. It is Z. B. possible that the ballast is removed from the lamp socket. Even then, it may be appropriate to equip the connection adapter of the LED light with a transformer, which in turn converts the mains voltage into the required DC voltage. Alternatively, there is the possibility of the conventional ballast not simply to remove, but to replace it with a suitable transformer, so that the modified lamp socket then already provides the required DC voltage available. In this case, it is then possible to dispense with a transformer integrated in the connection adapter.

Finally, it is also within the scope of the invention to make completely new housings and / or sockets for the LED lighting fixture. This is especially useful for new installations. Overall, the lighting fixture produced in the manner according to the invention is thus characterized by high flexibility.

In principle, it is possible to embed the LED functional band by means of simple plastic extrusion into only a single plastic, preferably a transparent plastic. Then it is expedient if this plastic after extrusion and thus after cooling has sufficient stability, so that the separated LED strip is sufficiently dimensionally stable and can be mounted self-supporting after mounting the connection adapter readily in a lamp holder.

However, the LED strip is particularly preferably produced continuously by way of coextrusion with at least one transparent core layer of a first transparent plastic and at least one transparent-scattering front layer of a second plastic. The invention is based on the (basically known) knowledge that, in particular with elongated luminous bodies, a "homogeneous" illumination is desired without the individual light-emitting diodes being discernible as discrete luminous dots. Consequently, the transparent-scattering front layer, as if it were a scatter layer or leveling layer, ensures that the luminous element has a uniform radiation characteristic over the length and width, without the individual ones LEDs can be perceived by the viewer as point light sources. This can be achieved, for example, by producing the transparent-scattering front layer from a different plastic than the highly transparent or crystal-clear core layer in which the light-emitting diodes themselves are embedded. Consequently, the transparent-scattering front layer can be a layer which is opaque as it were. Additionally or alternatively, the transparent-scattering character of the front layer can also be influenced by the geometric design and in particular the surface design. For example, the front layer may have a structured and / or profiled surface, wherein such a surface further enhances the deliberately desired scattering effects and consequently likewise leads to a homogeneous emission characteristic. In practice, it will be preferable to choose a combination of material selection on the one hand and geometry on the other hand. In any case, it is possible on the basis of LEDs to produce lighting fixtures which, like a fluorescent lamp, have a homogeneous emission characteristic over the entire length, without this, however, being associated with the disadvantages of the known fluorescent tubes.

Of particular importance in the context of the invention is the fact that the lighting fixture is ultimately composed essentially of the separated LED strips and the end-mounted adapters and that the LED tapes consequently do not have to be used in a complex manner in a separate housing. For this purpose, the already mentioned dimensional stability of the LED strip can be advantageous. The LED strip is therefore particularly preferably produced continuously by way of coextrusion with a stabilizing base layer consisting of a second or third plastic which is additional to the core layer and possibly the front layer. This rear base layer thus forms a stable base housing, which, however, by way of coextrusion integral with the entire LED strip is manufactured. While the optical properties are generally important for the transparent core layer and / or the transparent-scattering front layer, the base layer is primarily intended to ensure the stability of the LED strip produced in this way, with the result that the LED strip subsequently actually does not can install further processing steps and in particular without the use of another housing or other housing components. Consequently, while the transparent core layer preferably consists of a highly transparent plastic and the optionally provided transparent-scattering front layer also consists of a transparent or opaque or at least partially transparent material, it is generally not necessary to manufacture the base layer from a transparent plastic. It is rather within the scope of the invention that the base layer is made of a non-transparent plastic. This also makes it possible to influence the radiation characteristic, in particular when it is desired to dispense with lateral and / or rear-side radiation. The base layer may, in addition to the core layer of a first plastic form an additional, second layer of a second plastic. If a front layer is provided in addition to a core layer, the base layer forms an additional layer of a third plastic.

Alternatively, however, it is also possible to work without a stable base layer. Then it is useful if the core layer itself (sufficiently) is formed dimensionally stable.

For example, an elastomeric or flexible material may be used for the transparent core layer. Here, it is particularly appropriate for the transparent core layer to use a plastic material with a relatively low softening point or melting point, so that the LED functional band is embedded in the course of plastic extrusion in a melt having a temperature of less than 150 ° C, preferably less than 140 ° C, more preferably up to 130 ° C. In this way, damage to the LED function band and in particular the electronic components are avoided. The transparent core layer is preferably made of a highly transparent plastic, for. B. polyurethane (PU or TPU).

The front layer can basically be made of the same material as the transparent core layer. It can also be used polyurethane. Alternatively, the front layer can also consist of polycarbonate (PC) or PMMA.

The base layer is preferably made of a luminaire supporting the dimensionally stable plastic. Polycarbonate or PMMA can also be used here. It is also possible to use plastics with a higher softening point or melting point for the base layer, in particular if the arrangement ensures that the sensitive components of the LED functional strip do not come into contact with this hotter melt. The base layer can also consist of PU.

In particular, if the plastics used are processed at significantly different temperatures, it may be expedient to embed the LED functional band completely in the core layer, which is usually extruded at relatively low temperatures. Optionally, it is possible to embed the LED function band only partially in this core layer, in particular or at least in the region of the light-emitting diodes. Other parts of the LED function band, eg. B. the area of Carrier tape, for example, can be embedded in the stable base layer.

It has already been mentioned that the optionally provided base layer forms, as it were, a housing produced in one piece with the lighting fixture. Against this background, it is expedient that the base layer is formed in a trough-shaped or funnel-shaped cross-section so that the base layer surrounds the core layer to form obliquely and / or curvedly extending boundary surfaces (in regions). In cross-section, the base layer may thus form a trough or funnel, in which the LED function band is arranged at least partially and which is filled as it were with the transparent core layer, although the production takes place simultaneously and integrally by way of coextrusion. Optionally, it is further expedient if the depression formed by the base layer, in which the core layer is arranged, is closed on the front side by the transparent-scattering front layer. Also, this is - as already explained - produced by coextrusion in one piece with the other components.

The LED strip produced in the described manner can basically have different cross-sectional shapes. So z. B. a rectangular cross-sectional shape with a substantially planar front surface conceivable. However, it is optionally also within the scope of the invention if the LED strip has a convex (outwardly) curved front surface which is formed, for example, by a convexly curved front layer. In this embodiment too, the LED strip or the LED strip as a whole may have a substantially rectangular cross-sectional shape, but with a curved front layer.

Alternatively, however, the LED strip or the LED strip may also have a circular or circular segment-shaped cross section or else an annular or ring segment-shaped cross section. These cross-sectional shapes have the advantage that they can coincide, for example, with the known cross-sectional shapes of conventional fluorescent tubes, so that the end caps can be adapted in their dimension to the usual plug. In particular, in such embodiments with a circular or kreissegmentförmigem or annular or ringsegmentförmigem cross section, it is advantageous if the LED function band is embedded in a bent around its longitudinal axis state in the plastic, wherein the LEDs are then preferably aligned with the center of curvature.

In such a curved variant, preferably at least the core layer is curved and thus formed in cross-section annular segment, wherein on the center of curvature inner side facing a curved front layer may be arranged, which has the already described scattering properties. It is within the scope of the invention that the LED strip is formed only by such a curved core layer with a likewise curved front layer arranged thereon. Then it is useful if the core layer is made of a sufficiently dimensionally stable plastic. Alternatively, however, it is also possible to provide an additional base layer, which likewise can be curved in a corresponding manner and thus formed in the manner of a ring segment. Optionally, the base layer may be circular in cross-section, in which case the ring-segment-shaped core layer and the possibly provided front layer may be completely integrated into this core layer. In this embodiment, the LED strip is substantially of a circular in cross-section, solid base layer of transparent Material or partially transparent material formed in which the core layer and thus also embedded in the core layer LED function band is integrated.

According to a further proposal with particular importance, contact elements which are designed for contacting with the connection caps can be integrated into the LED function band in the predetermined spacing defining the length of the LED strip. These contact elements may be z. B. act contact sleeves or pins, which are integrated at predetermined intervals with in the LED function band and then embedded in the LED strip. After appropriate assembly, these contact elements are exposed so that in a simple manner suitable end caps can be attached, being plugged in the course of this Aufsteckens example contact elements of the end caps in contact sleeves or plugged onto pins.

According to a further proposal of the invention, one or more thermocouples can be introduced into the LED strip or into the LED strips, preferably directly during the extrusion. These thermocouples are particularly preferably integrated in the base layer in a multilayer structure. These thermocouples allow temperature monitoring and thus efficient energy management of the luminaire.

Figur 1

einen erfindungsgemäßen Beleuchtungskörper als Ersatz für eine herkömmliche Leuchtstofflampe,

Figur 2

einen vereinfachten Querschnitt durch den in Figur 1 dargestellten Beleuchtungskörper,

Figur 3

eine abgewandelte Ausführungsform des Gegenstandes nach Figur 2,

Figur 4

eine dritte Ausführungsform der Erfindung und

Figur 5

eine vierte Ausführungsform der Erfindung.

In the following the invention will be explained in more detail with reference to a drawing showing only one exemplary embodiment. Show it

FIG. 1

a lighting fixture according to the invention as a replacement for a conventional fluorescent lamp,

FIG. 2

a simplified cross section through the in FIG. 1 illustrated lighting fixtures,

FIG. 3

a modified embodiment of the article according to FIG. 2 .

FIG. 4

a third embodiment of the invention and

FIG. 5

A fourth embodiment of the invention.

In the figures, a lighting fixture 1 is shown, which forms a luminaire replacement for a conventional fluorescent lamp. In addition shows FIG. 1 a conventional lamp holder 2 for a conventional fluorescent lamp, in which lamp holder 2, an inventive lighting fixture 1 is based on LEDs used. The lighting fixture 1 according to the invention is produced as follows:

First, an LED functional band in an extrusion device is embedded continuously into at least one thermoplastic material to form an LED band. The starting point of the production forming LED function band 3 generally has a (flexible) carrier tape 4, on or in which conductor tracks and optionally further electrical or electronic components are arranged. In particular, a plurality of light-emitting diodes 5 are arranged on the LED function band.

After extrusion and thus after production of the (endless) LED strip, this LED strip is divided into a plurality of LED strips 6 of predetermined length. In the exemplary embodiment, a connection adapter 7 is now mounted at both ends of such an LED strip 6. The one with the connection adapters 7 provided LED strips then forms without significant further modification of the lighting fixture 1, which as a replacement for a conventional fluorescent lamp in the in FIG. 1 indicated lamp socket 2 can be mounted.

The FIGS. 2 and 3 show embodiments of the invention in which the LED strip from which the LED strips 6 are made, is produced continuously by way of coextrusion. In the FIGS. 2 and 3 it can be seen that the LED strip or the LED strip has a transparent core layer 8 made of a first plastic material and a transparent-scattering front layer 9 made of a second plastic material. Furthermore, as a third layer, a base layer 10 likewise produced by way of coextrusion can be seen, which is made of a third plastic.

The transparent core layer 8 is usually made of a highly transparent or crystal clear plastic material and in this transparent core layer 8 and at least the light-emitting diodes 5 of the LED function band 3 are integrated. In contrast, the front layer 9 has scattering properties, so that the lighting fixture 1 as a whole does not generate any punctiform light but ensures uniform illumination. In the exemplary embodiments, it is indicated that this front layer 9 has a structured surface.

The base layer 10 is made in the embodiment of a non-transparent plastic. It forms as it were the integrally manufactured housing and is designed as a self-supporting, dimensionally stable layer.

In the illustrated embodiments, the LED function band 3 is both partially in the base layer 10 and partially in the core layer 8 embedded. It is indicated that at least the LEDs 5 of the LED function band 3 are embedded in the region of the core layer 8, while the carrier tape 4 is at least partially embedded in the base layer 10.

The base layer 10 is formed trough-shaped or funnel-shaped. It surrounds the core layer 8 in regions. This means that in the recess formed by the base layer 10, the core layer 8 is integrated, wherein the front layer 9 is applied to the front side of the core layer 8, so that the recess formed by the base layer 10 is as it were closed by the front layer 9. The trough-shaped or trough-shaped configuration of the base layer 10 produces boundary surfaces running obliquely between the core layer 8 and the base layer 10 in relation to the base surface. These interfaces are in the embodiment at an angle α of about 20 ° to 60 °, z. B. arranged about 40 ° to 50 °.

While the embodiment according to FIG. 2 has a substantially flat - but structured - front surface, the front surface in the embodiment according to FIG. 3 curved.

It is also in FIG. 3 indicated that in the lighting fixture, z. B. in the base layer 10 in addition thermocouples 12 may be integrated to provide for efficient energy management.

While the FIGS. 1 to 3 Embodiments show in which the LED strips or LED strips have a substantially rectangular cross-section, the show FIGS. 4 and 5 modified embodiments in which the LED strip or the LED strip has a circular or ring-segment-shaped cross-section. In these embodiments embedded in the plastic and in particular in the core layer 8 in a state curved about its longitudinal axis of the LED function band. This has the consequence that the LEDs 5 are aligned with the center of curvature.

In the embodiment according to FIG. 4 The LED strip has a circular segment-shaped cross-section. In this case, the transparent core layer 8 is curved and thus formed in cross-section annular segment. On the inner side of the center of curvature facing a scattering front layer 9 is arranged. In this embodiment, the LED tape is formed solely by the curved core layer 8 and the front layer 9.

In the modified embodiment according to FIG. 5 an additional base layer 10 is provided, wherein the circular segment-shaped core layer 8 is completely integrated with the front layer 9 in the base layer 10. The base layer 10 has a circular cross section, so that the LED strip as a whole has a circular cross section. In this embodiment, the base layer 10 is also made of a transparent plastic.

Incidentally, in FIG. 4 exemplified that in the LED function band contact elements 11 may be integrated, which are designed for contacting the ready-made LED strip with a aufzusteckenden connection cap or end cap 7. These connection elements 11 are preferably integrated into the LED function band at predetermined intervals, which define the length of the LED strips. After extrusion and after assembly of the LED strip, these contact elements 11 are exposed, so that simply corresponding connection caps can be attached. The contact elements 11 may, for example, as sleeves or be designed as pins, so that corresponding mating contact elements can be inserted into these sleeves or attached to these sleeves. Details are not shown.

Claims (21)

1. Method for producing a lighting body (1) on an LED basis, particularly as a lighting replacement for a fluorescent lamp,
   wherein a LED functional strip (3) furnished with a plurality of light-emitting diodes is continuously embedded in at least one thermoplastic synthetic material in an extrusion device, thereby forming an LED strip,
   wherein the LED strip is subsequently divided into a plurality of LED strips (6) of prescribed length, and
   wherein one or more connection adaptors (7) are fastened to one or both ends of an LED strip, characterised in that the lighting body formed by the LED strip with the attached connection adaptors can be mounted in a lamp socket.
2. Method according to claim 1, wherein the LED strip is manufactured continuously by co-extrusion from multiple layers and/or multiple thermoplastic synthetic materials with, for example, at least one transparent core layer (8) made from a first thermoplastic synthetic material and at least one transparent scattering front layer (9) made from a second thermoplastic synthetic material.
3. Method according to claim 2, wherein the LED strip is manufactured continuously by co-extrusion with a further stabilising base layer (10) made from a second or third thermoplastic synthetic material in addition to the core layer and the optional front layer.
4. Method according to either of claims 2 or 3, wherein the transparent core layer is made of highly transparent plastic, for example polyurethane (PU).
5. Method according to any one of claims 2 to 4, wherein the front layer is made of PU, PC or PMMA.
6. Method according to any one of claims 3 to 5, wherein the base layer is manufactured from transparent or non-transparent plastic, for example, PU, PC or PMMA.
7. Method according to any one of claims 3 to 6, wherein the base layer is manufactured as a dimensionally stable layer that supports the lighting body.
8. Method according to any one of claims 2 to 7, wherein the LED functional strip is embedded in the core layer completely or at least in the area of the LEDs.
9. Method according to any one of claims 2 to 8, wherein the LED functional strip, or at least portions thereof, is/are embedded in the base layer, for example in the area of the carrier strip.
10. Method according to any one of claims 3 to 9, wherein the cross section of the base layer is conformed with a depression and surrounds areas of the core layer, forming boundary surfaces that extend in a slanted and/or curved manner relative to a base surface.
11. Method according to claim 10, wherein the recess formed by the base layer, in which the core layer is arranged, is closed at the front by the front layer.
12. Method according to any one of claims 2 to 11, wherein the front layer is constructed as a layer with convex or concave curvature.
13. Method according to any one of claims 2 to 12, wherein the front layer has a structured or profiled surface.
14. Method according to any one of claims 1 to 13, wherein the LED strip manufactured by extrusion has a rectangular cross-section or a cross-section in a circular or circle-segment shape or a cross section in an annular or ring segment-shape.
15. Method according to any one of claims 1 to 14, wherein the LED functional strip is embedded in the synthetic material while curved about its longitudinal axis, wherein the light-emitting diodes are preferably aligned with the centre of curvature.
16. Method according to claim 15, wherein the core layer is curved and the cross section of which is in the shape of a ring segment, wherein the front layer, which is also curved, is arranged on the inner side facing towards the centre of curvature.
17. Method according to claim 16, wherein the cross section of the base layer is circular, wherein the core layer in the shape of a ring-segment and optionally a front layer is/are fully integrated in the base layer.
18. Method according to any one of claims 1 to 17, wherein contact elements are integrated in the LED strip at the predefined distances defining the length of the LED strip, which contact elements are designed for making contact with a terminal cap.
19. Method according to claim 18, wherein the contact elements integrated in the LED functional strip are in the form of contact sleeves or contact pins, into or onto which the contact elements of the terminal cap are inserted or plugged.
20. Method according to any one of claims 1 to 19, wherein one or more thermocouples is/are embedded in the thermoplastic synthetic material, for example in the base layer and/or the core layer.
21. Lighting body on an LED basis, particularly as a lighting replacement for a fluorescent lamp, manufactured according to a method according to any one of claims 1 to 20.

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