EP2118562A1

EP2118562A1 - Led lamp with omnidirectional light radiation and optimized heat dissipation

Info

Publication number: EP2118562A1
Application number: EP07857088A
Authority: EP
Inventors: Christoph Kuegler
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-12-22
Filing date: 2007-12-21
Publication date: 2009-11-18
Anticipated expiration: 2027-12-21
Also published as: CN101641551A; US20110038152A1; EP2118562B1; WO2008077627A1; DE102006061020B3; US8382320B2; CN101641551B

Abstract

An LED lamp comprises a plurality of angular carriers (Li). Moreover, the angular carrier sections (2.i) of the carriers (1.i) are adjacent. The solid angles of the surface of the angular carrier sections (2.i) correspond substantially to different solid angles of a polyhedron. The LED lamp furthermore has a plurality of LED elements (4.i) which are disposed on the angular carrier sections (2.i). The heat of the individual LED elements (4.i) emanating from the angular carrier section (2.i) is dissipated over the remaining carrier (3.i).

Description

LED illuminant with omnidirectional light emission and optimized heat dissipation

The invention relates to an LED light source (LED - light emitting diode), a lamp comprising such an LED light source and a method for producing such a light source.

Illuminants are the light-emitting objects of a luminaire. Examples of common bulbs are incandescent (also referred to as light bulbs), halogen bulbs or fluorescent lamps. Due to the progressive development in the field of LEDs, LEDs are becoming increasingly interesting as lighting devices for fields of application in which incandescent lamps, halogen incandescent lamps or fluorescent lamps are currently predominant.

An LED is a diode-based semiconductor device. When current flows through the diode in the forward direction, it emits light. By choosing the semiconductor material and the doping, the wavelength of the emitted light can be influenced.

LEDs that produce white light (white LEDs) can be made by covering a blue LED with fluorescent dye. Alternatively, a plurality of light-emitting diodes, which emit light in different colors, can be connected together so that white light results due to the color addition. White LEDs are available as SM D components (surface mounted device), which can be soldered directly to an electrical circuit board using solderable connection surfaces. Furthermore, are white LEDs already finished on a printed circuit board (for example, mounted on a square board with the dimensions 25x25 mm ² ) available.

Important parameters of a light source are its luminous efficacy in lumens per watt (Im / W) and its power consumption. Presently commercially available white LEDs typically have a light output of up to 50 lm / W and an absolute power consumption of 2.5 W per LED. The luminous efficacy of white LEDs is thus higher than that of incandescent and halogen incandescent lamps (typically in the range of 10 Im / W to 20 Im / W), but below that of fluorescent lamps (up to 110 Im / W).

To replace a conventional bulb such as an incandescent bulb or a halogen incandescent bulb, an LED bulb should deliver a comparable luminous flux. For example, a common 75W incandescent bulb for high voltage operation (i.e., at 230V or 110V line voltage) has a luminous flux of approximately 900 Im. To achieve approximately half the luminous flux of such a 75W incandescent lamp with an LED illuminant, for example, 4 white LEDs with 50 Im / W and a power of 2.5 W per LED can be interconnected, resulting in a luminous flux of 500 Im.

Due to their design, LEDs have the disadvantage that individual LEDs, in contrast to incandescent lamps having an almost omnidirectional radiation characteristic, only achieve a radiation angle range of typically 120 ° to a maximum of 180 °.

When connecting several LEDs, it must be ensured that the heat loss of the LEDs is adequately dissipated, otherwise the LEDs will overheat and be destroyed. From the document DE 200 13 605 U1 an elongated tubular light source is known, which has a plurality of SMD LEDs as the light source. Chains of SMD LEDs are mounted on the surface of a hollow body.

Furthermore, the publication DE 10 2004 004 947 A1 discloses a luminous means which has the shape of a conventional incandescent lamp. For this purpose, several LEDs are mounted on a cube or octahedral carrier inside the bulb. A disadvantage of such an arrangement is that the carrier does not ensure sufficient heat dissipation.

It is therefore an object of the present invention to provide an LED light source, which has a possibly omnidirectional radiation characteristic with sufficient heat dissipation at a sufficiently large luminous flux. It is another object of the invention to provide a method for producing such a light source.

The objects underlying the invention are achieved by the features of the independent claims.

The LED lighting device according to the invention according to claim 1 comprises a plurality of carriers, which are advantageously similar. The carriers are each angled. Advantageously, the supports are angled metal sheets.

Furthermore, the carriers are arranged such that the angled carrier portions of the carrier are adjacent, so lie together. The solid angles of the surfaces of the angled support sections substantially correspond to different solid angles of a polyhedron. It can be provided that not only the solid angles correspond to those of a polyhedron, but also that the angled Trägerabεchnitte in shape and - A -

Arrangement to one another substantially correspond to the sides of a polyhedron.

According to the invention, the LED illuminant further comprises a plurality of (advantageously white) LED elements, for example white LED SMDs, which are arranged on the angled carrier sections. Advantageously, at least one LED element is arranged on each angled support section. The heat of the individual LED elements is in each case removed from the angled carrier section via the remaining carrier. An LED element in the sense of the application can be both a single LED and an LED with associated board.

Due to the arrangement of the LED elements in different polyhedron solid angles, an omnidirectional radiation characteristic of the LED light source can be achieved. Since angled carriers are provided for the individual LED elements, the heat of the individual LED elements, starting from the angled carrier section, can be dissipated via the remaining carrier in a sufficient manner. Due to the use of angled carriers, a further cooling surface is provided for each LED element next to the surface on which the LED element is arranged and which corresponds to the angled carrier section, which corresponds to the rest of the carrier. As a result, the surface available for heat dissipation is significantly increased.

It should be noted that an angled support has not necessarily been created by bending a straight output carrier. Such a carrier can also result by joining two carrier parts at an angle.

Furthermore, the LED illuminant is not necessarily made by assembling separate angled carriers. For example, it can also be - O -

be seen that first the support sections on which the LED elements are arranged or arranged later, are joined together, and then the angled support sections are attached.

Advantageously, for at least two carriers whose angled support sections adjoin one another, the inner angle between the angled support section and the remaining support corresponds to half of the outer angle between the adjoining angled support sections of these two supports. As a result, the shading by the rest of the carrier, which serves to dissipate heat can be minimized.

According to an advantageous embodiment, two or more carriers, in particular all carriers, are arranged parallel to a common axis. It is advantageous if a first group of carriers extends in one direction along the common axis, while a second group of carriers extends in the opposite direction along the common axis.

It is advantageous if the angled support sections essentially correspond to different side surfaces of a polyhedron or parts of these side surfaces, so that the adjacent support sections can be arranged such that they form a polyhedron.

Advantageously, the LED illuminant has at least four LED elements. Even with a beam angle range of 120 ° per LED element, a nearly omnidirectional radiation characteristic can be achieved.

The polyhedron may be a platonic body in which the side surfaces are regular polygons that are congruent to each other, of which the same number coincide in each corner. Tetrahedron (4 Pages), hexahedron (6 pages), octahedron (8 pages), dodecahedron (12 pages) and icosahedron (20 pages) each form a platonic solid. Accordingly, it may be advantageously provided that the polyhedron is a tetrahedron and the LED illuminant comprises four angled support sections, the solid angles of the four angled support sections essentially corresponding to the four solid angles of the tetrahedron. In particular, the four angled support sections may substantially correspond to the surfaces of a tetrahedron in shape and arrangement with respect to one another. By arranging the angled carrier sections corresponding to the solid angles of a tetrahedron, a nearly omnidirectional emission characteristic can already be produced with 4 LEDs.

If two or more carriers are arranged along a common axis, it is advantageous for the carriers to form a channel along this axis, for example by curving the carriers about the common axis. As a result, the heat can be dissipated via the insides of the carrier.

In order to further improve the heat dissipation, the carriers can advantageously be mounted on a bar press profile, for example on an aluminum bar press profile. In this case, the heat is dissipated via the thermally well-conducting bar press profile.

To increase the surface area of the carriers it can be provided that the carriers have holes. Due to the thereby enlarged surface heat dissipation is further improved.

Advantageously, the LED lighting means each comprise a socket. This should advantageously be a common bulb socket for high-voltage operation (typically 230 volts or 110 volts) or low-voltage operation

(typically 12 volts). This allows the use of the LED Illuminant as a replacement for common bulbs, such as incandescent or halogen bulbs.

Furthermore, an electronic ballast (transformer) is advantageously provided in the LED lighting means.

The luminaire according to the invention as claimed in claim 21 comprises an above-described LED lighting means.

The method according to the invention for producing an LED light-emitting means according to claim 23 comprises a plurality of steps. In a first step, a plurality of angled carriers are provided. In each case a plurality of LED elements are arranged on the angled carrier sections, with the heat of the individual LED elements each being removed from the angled carrier section via the remaining carrier during operation of the LED illuminant. In a further step, the carriers are arranged such that the angled carrier sections are adjacent and the solid angles of the surfaces of the angled carrier sections substantially correspond to different solid angles of a polyhedron.

Further advantageous embodiments of the invention are specified in the subclaims.

The invention will be explained in more detail with reference to several embodiments with reference to the drawings; in these show:

1 shows a first embodiment of the LED according to the invention

Illuminant with tetrahedral arrangement of the angled carrier sections; Fig. 2 is an ideal tetrahedron;

3 is a radiation diagram of the LED shown in FIG.

Lamp;

4 shows a second exemplary embodiment of the LED illuminant according to the invention with a tetrahedral arrangement of the angled carrier sections and perforation of the cooling plates;

5 shows a third embodiment of a LED according to the invention

Illuminant with tetrahedral arrangement of the angled support sections and tubular curvature of the cooling plates;

6 shows a fourth embodiment of a LED according to the invention

Illuminant with six LEDs;

Fig. 7 is an ideal cuboctahedron;

FIG. 8 is a radiation diagram of the LED illuminant shown in FIG. 6; FIG. and

9 shows an LED lamp with a socket, a transformer

Housing and an optional glass or plastic housing.

The following table shows the luminous efficacy and the total power loss of a white LED illuminant in the light color warm white (about 3500 K) depending on the number of white LEDs used and the LED characteristics (power per LED in watts and luminous efficacy in Lumen per watt). A low luminous flux is in the range of 500 to 750 Im, a high luminous flux is from 1000 Im. Furthermore, it can be assumed that with a total power loss from 30 W, the bulb is very hot. At a total power loss over 40 W, the bulb becomes too hot, so it is destroyed.

White LEDs with a power loss of 2.5 W and a luminous efficacy of 50 Im / W are already available at the present time It is assumed that from 2008 white LEDs with a power loss of 5 W per LED and a luminous efficacy of 50 Im / W or alternatively with a power dissipation of 2.5 W and a luminous efficacy of 70 Im / W will be commercially available

As can be seen from the table above, to replace a standard 75W incandescent lamp with approximately 900 in the luminous flux, at least four, better six, white LEDs with a luminous efficiency of 50 Im / W and a power of 2.5 W per LED should be interconnected a luminous flux of 500 Im or 750 Im results

1 shows a first exemplary embodiment of the inventive LED light source with four white LEDs 4 ι with ι = 1, 2, 3 and 4 The representation of the housing, the socket and the electrical circuit components for driving the LEDs has been omitted The LED bulb comprises four angled Trager 1 ι, with a single carrier 1 ι in an angled Tragerabschnitt 2 ι and the rest Trager 3 ι subdivide let Em deraφger carrier 1! does not necessarily have to be done by bending one straight one-piece output carrier may have been produced, but may also result by joining two carrier sections 2.i and 3.i at an angle. In this case, the two support sections 2.i and 3.i need not necessarily be made of the same material. The support 1.i preferably comprises an angled metal cooling plate, in particular an angled aluminum sheet.

On the angled support section 2.i at least one LED 4.i with the associated board (not shown) attached. Relative to the longitudinal extension of the carrier 1.i, the LED 4.i is asymmetrically mounted on the carrier 1.i. The board need not be limited to the angled support section 2.i, but may also extend to the remaining support 3.i. The carrier 1.i can also be part of the board; In this case, a circuit board layer, for example an aluminum oxide layer, assumes the function of the carrier. Preferably, in each case, the board with the LED

4.1 attached to the carrier Li.

The support sections 3.i are each arranged parallel to a common axis. In each case two carriers 1.i are arranged with their carrier sections 3.i parallel to one another. The two parallel carriers 1.1 and

1.2 extend in one direction along the common axis, while the two other mutually parallel support 1.3 and 1.4 extend in the direction opposite thereto along the common axis. The inner angle between the bent support section 2.i and the associated support section 3.i corresponds to half the outer angle between two angled support sections 2.i of two parallel supports Li.

As can also be seen from FIG. 1, the four carriers Li, each with an LED 4.i mounted thereon, are arranged such that the LEDs 4.i on the angled carrier sections 2.i are at solid angles which essentially correspond to the solid angles of a polyder , here a tetrahedron, speak. This allows an omnidirectional radiation characteristic. For the approximate formation of a spotlight, the LEDs 4.i on the angled support sections 2.i should be brought together as closely as possible. Therefore, in Fig. 1, not only the solid angles of the angled support portions 2.i correspond to those of a tetrahedron, but the angled support surfaces 2.i together also substantially form a tetrahedron. For comparison, an ideal tetrahedron is shown in FIG.

For arranging the angled carrier sections in tetrahedral form, the angled carrier sections 2.i taper towards their end in the form of a substantially isosceles trapezium. Alternatively, the angled support section 2.i could also be executed in the form of an equilateral triangle.

During operation of the LED illuminant, the heat loss of the individual LED 4.i can be dissipated sufficiently from the angled support section 2.i via the support section 3.i. Because of the use of angled carrier Li, a further cooling surface in the form of the carrier section 3.i is provided for each LED 4.i next to the surface 2.i, on which the respective LED 4.i is arranged. As a result, the available surface for heat dissipation is significantly increased, so that the thermal resistance decreases.

FIG. 3 shows the radiation pattern of the LED illuminant illustrated in FIG. 1. In the radiation diagram, the individual radiation components 5.i of the LEDs 4.i are shown, which have been projected into a common plane. Each LED 4.i has a beam angle of 120 °. The total radiation results from the superposition of the individual radiation components 5.i. As can be seen from FIG. 3, the LED illuminant according to FIG. 1 has an omnidirectional emission characteristic. FIG. 4 shows a second exemplary embodiment of an LED illuminant according to the invention. Components of the two luminous means in FIGS. 1 and 4 provided with the same reference symbols correspond to one another. In contrast to the luminous means shown in FIG. 1, in the luminous means in FIG. 4 the supports 1.i, in particular the support sections 3.i, have holes 6. Preferably, the holes are produced by punching a cooling plate. Due to the holes 6 in the carrier Ii, the surface available for heat dissipation is increased, so that the thermal resistance decreases.

Fig. 5 shows a third embodiment of an LED lamp according to the invention. Components of the two lamps in FIGS. 1 and 5 provided with the same reference symbols correspond to one another. In contrast to the illuminant illustrated in FIG. 1, in the illuminant illustrated in FIG. 5, the support sections 3.i are curved about the common axis, so that the support sections 3.i essentially form a tubular heat sink. As a result, the available surface for heat dissipation is further increased, since the opposite side surfaces of the support sections 3.1 and 3.2 or 3.3 and 3.4 are used for thermal coupling of the heat sink to the environment of the heat sink. The thermal resistance can be further reduced if the carriers Li are mounted on a bar press profile, in particular an aluminum bar press profile, so that the channel formed by the carrier sections 3.i is filled with the bar press profile.

6, a fourth embodiment of an LED light-emitting device according to the invention is shown. Components of the two light sources in FIGS. 1 and 6 provided with the same reference symbols correspond to one another. In contrast to the exemplary embodiment according to FIG. 1, six white LEDs are interconnected in the exemplary embodiment illustrated in FIG. 6, so that a larger luminous flux results compared with the exemplary embodiment shown in FIG. 1 with four white LEDs. As can be seen from the above table, when Zusarrirnenschaitung six - -

white LEDs with a luminous efficacy of 50 Im / W and a power of 2.5 W per LED reach a luminous flux of 750 Im.

As can be seen in FIG. 6, the carrier sections 3.i are arranged parallel to a common axis. Three carriers Ii, namely the carriers

1.1, 1.2 and 1.3 or 1.4, 1.5 and 1.6, lie with their support sections 3.i each other. The three beams 1.1, 1.2 and 1.3 extend into one

Direction along the common axis, while the carrier 1.4, 1.5 and 1.6 extend in the direction opposite thereto along the common axis.

The carriers Li, each with an LED 4.i arranged thereon, are arranged so that the solid angles of the angled carrier sections 2.i substantially correspond to six selected solid angles of a cuboctahedron with a total of 14 side surfaces and thus 14 solid angles. For comparison, an ideal cuboctahedron is shown in FIG. Here, the surface shape of the angled support sections 2.i does not have to correspond to the surface shape of the side surfaces of a Kuboktaeders. Thus, the angled support sections 2.i illustrated in FIG. 6 each have the area of a triangle, while the cuboctahedron shown in FIG. 7 comprises both triangles and squares as side surfaces.

Similar to the embodiment shown in Fig. 5 with curved support sections 3.i are the opposite side surfaces of the support sections 3.1, 3.2 and 3.3 or 3.4, 3.5 and 3.6 free, so that these surfaces for thermal coupling of the heat sink to the environment of the heat sink be used. Furthermore, as in the exemplary embodiment in FIG. 5, the carriers 1.i can also be mounted on a bar press profile, so that the thermal coupling of the opposite side surfaces of the carrier sections 3.i to the surroundings is further improved. FIG. 8 shows the radiation pattern of the LED illuminant illustrated in FIG. 6. In the radiation diagram, the individual radiation components 5.i of the LEDs 4.i are shown, which have been projected into a common plane. Each LED 4.i has a beam angle of 120 °. The total radiation results from the superposition of the individual radiation components 5.i. As can be seen from FIG. 8, the LED illuminant according to FIG. 1 has an omnidirectional emission characteristic. Due to the use of six LEDs 4.i and thus greater overlap of the cone-shaped radiation space angle of the individual LEDs, the angular dependence of the radiation is less than in the radiation pattern shown in Fig. 3 with four LEDs 4.i.

FIG. 9 schematically shows a finished LED illuminant with a socket 6, a transformer housing 7 and an optional glass or plastic housing 8. The LED illuminant further comprises a carrier arrangement equipped with LED elements, for example the carrier arrangement according to FIG. 1. Alternatively, the carrier arrangements illustrated in FIGS. 4, 5 and 6 may also be included. The version 6 shown in FIG. 9 is a socket for common 230VoIt or 12VoIt lamps; for example, a version of the type E14, E 27, G9, B15d or R7s in the case of a high-voltage version or a version of the type Gy6.35, Gx5.3 in the case of a low-voltage version. In addition, the version can be socketed on two sides instead of unilaterally. The transformer housing 7 surrounds electrical circuit components (not visible) which are used to control the LEDs. Preferably, in AC mode, the circuit components include a transformer which reduces the voltage on the socket (eg 230V or 12V) to a lesser value. In addition, a rectifier is provided in AC operation. Since the LEDs are operated at a constant current, the electrical circuit components preferably include circuit means (eg, a bias resistor or a JFET current source) for operating the constant current LEDs. Connected to the electrical circuit components is the carrier arrangement whose LEDs are controlled by the electrical circuit components. The electrical But trical circuit components can also be partially or even completely mounted on the carrier assembly.

Optionally, a translucent glass or plastic housing 8 is provided, which surrounds the support arrangement and, for example, has a tubular design. In this case, the housing 8 may be made of clear or frosted glass or plastic.

A light-emitting means as shown in FIG. 9 is suitable as a replacement for conventional light sources, in particular for common incandescent lamps or halogen incandescent lamps.

Claims

ClaimsLED lamps with omnidirectional light emission and optimized heat dissipation

1. LED lighting, comprising

- A plurality of carriers (Li), which are each angled, wherein the carrier (1.i) are arranged such that the angled

Carrier sections (2.i) are adjacent and the solid angles of the surfaces of the angled support sections (2.i) correspond to different solid angles of a polyhedron substantially, and

a plurality of LED elements (4.i) which are arranged on the angled carrier sections (2.i), wherein the heat of the individual LED elements (4. i) in each case starting from the angled carrier section (2. i) via the other carrier (3.i) is discharged.

2. LED illuminant according to claim 1, d ad u rch ge ke n nze net net, d ass for at least two carriers (1.1, 1.2), whose angled support sections (2.1, 2.2) adjoin one another, the inner angle between the angled support portion ( 2.1, 2.2) and the rest of the support (3.1, 3.2) of the half of the outer angle between the adjacent angled support sections (2.1, 2.2) of these two carriers

(1.1, 1.2).

3. LED luminous means according to one of the preceding claims, d ad u rc hze nets et n, d the at least two of the carriers (Ii) are arranged parallel to a common axis.

4. LED luminous means according to claim 3, characterized in that a first group of carriers (1.1, 1.2) extends in one direction along the common axis, while a second group of carriers (FIG. 1.3, 1.4) extends in the opposite direction along the common axis.

5. LED luminous means according to one of the preceding claims, characterized in that there are two identical carriers (1.i).

6. LED illuminant according to one of the preceding claims, characterized in that there is at least one LED element (4.i) on each angled support section (2.i.), in particular exactly one LED element. Element, is arranged.

7. LED illuminant according to one of the preceding claims, which show that the angled support sections (2.i) essentially correspond to different side surfaces of a polyhedron or parts of these side surfaces.

8. LED lighting device according to claim 7, dad u rch g eken Ize net that the angled support sections (2.i) essentially form a polyhedron.

9. LED lighting device according to one of the preceding claims, dad u rch geke nnze I net, that the LED lighting means at least four LED elements (4.i), in particular exactly four, six or eight LED elements (4.i ).

10. LED light source according to one of the preceding claims, dad u rch geken nze I net, that it is the polyhedron is a tetrahedron and the LED bulbs four angled support sections (2.i), wherein the solid angles of the four angled Carrier sections (2.i) substantially correspond to the four solid angles of the tetrahedron.

11. LED lighting device according to one of the preceding claims, dad u rch geken Ize net, that it is the polyhedron is a cuboctahedron and the LED light source comprises six angled support sections (2.i), wherein the solid angle of the six angled Carrier sections (2.i) substantially correspond to six different solid angles of the cuboctahedron.

12. LED bulbs according to one of the preceding claims, dad u rch geken Ize net, that it is the carriers (1.i) are angled metal sheets.

13. LED lighting device according to claim 3 or according to one of the dependent on claim 3 claims 4 to 12, d ad u rch geken designated, d the carriers (1.i) along the common axis form a channel.

14. LED lighting device according to claim 3 or according to one of the dependent on claim 3 claims 4 to 13, d ad u rch geken net nets, the d ass's (1, i) are curved about the common axis.

15. LED lighting device according to claim 3 or according to one of the dependent on claim 3 claims 4 to 14, dad u rch geken characterized, d the carriers (Li) are mounted on a bar press profile.

16. LED luminous means according to one of the preceding claims, dad u rch geken designated, d a the carrier (Li) to increase the surface holes.

17. LED lighting device according to claim 3 or according to one of the dependent claims 4 to 16 on claim 3, dad u rch geken nzeich net, d a one or more electrical circuit components for operating the LED elements (4.i), in particular a transformer , is arranged at one end of the carrier assembly formed from the carriers.

IS. LED illuminating! according to one of the preceding claims The LED illuminant comprises a socket (6), in particular a socket for common 230Volt or 12Volt lamps.

19. LED luminaire according to one of the preceding claims, characterized in that the LED elements (4.i) emit white light in each case.

20. LED luminous means according to one of the preceding claims, d e r e w e ke n nze I net, d the LED illuminant has an omnidirectional radiation pattern.

21 light comprising an LED bulb according to any one of the preceding claims.

22. Use of an LED lamp according to claim 18 as a replacement for an incandescent or halogen incandescent lamp.

23. A method of manufacturing an LED bulb, comprising the steps

Providing a plurality of carriers (Li), which are each angled, and on the angled support portions (2.i) each have a plurality of LED elements (4.i) are arranged, wherein in the operation of the LED illuminant, the heat of a - Individual LED elements (4.i) each starting from the angled support section (2.i) on the remaining support (3.i) is removed; and

Arranging the carriers (Li) in such a way that the angled carrier sections (2.i) are adjacent and the solid angles of the surfaces Chen the angled support sections (2.i) correspond to different solid angles of a polyhedron substantially.