EP2126457A1

EP2126457A1 - Light source for simulating a spot light source, and lamp having such a light source

Info

Publication number: EP2126457A1
Application number: EP08715867A
Authority: EP
Inventors: Mario PÖHS
Original assignee: Zumtobel Lighting GmbH Austria
Current assignee: Zumtobel Lighting GmbH Austria
Priority date: 2007-02-26
Filing date: 2008-02-19
Publication date: 2009-12-02
Also published as: DE102007009229A1; DE102007009229B4; WO2008104309A1

Abstract

The invention relates to a light source, comprising a plurality of carrier elements (2), wherein the carrier elements each have a substantially plane surface section on which at least one, or two light emitting diodes are disposed. The carrier elements (2) disposed relative to each other such that the surface sections of the carrier elements define the surface of the convex polyhedron, such as a dodecahedron. The light source may be approximately considered as a spot light source such that it is suitable, for example, as a light source for a ball lamp.

Description

Light source for simulating a point light source, and light with such a light source

The present invention relates to a light source with a plurality of carrier elements, wherein the carrier elements each have a substantially planar surface portion, on which at least one light-emitting diode is arranged. Moreover, the invention relates to a luminous element with such a light source, as well as an arrangement of a plurality of such luminous bodies.

For the sake of simplicity, "light source" will be referred to below as a "light source unit", ie not just the actual light source, for example a light-emitting diode, but a unit which may comprise a plurality of components which serve to generate light. For example, components intended to drive or power the "actual" light source should also be understood as elements of the "light source".

Ball lights have a substantially spherical surface through which light can be radiated. The surface is formed by a translucent "light exit body", which may be made of glass or plastic, for example.

In the case of spherical luminaires, it may be desirable for the light exit body to be illuminated as evenly as possible from the inside, so that a luminaire is made possible which emits light in all directions as uniformly as possible, ie has the most homogeneous possible radiation.

An absolutely homogeneous illumination of a sphere can only be achieved with a point light source. A light bulb can serve as a point light source in a very good approximation with sufficiently large light emission body. However, a light source in the form of a light bulb causes certain disadvantages. For example, light can only be emitted in a certain color. The present invention is based on the object of specifying a light source for a luminaire, which can serve as a point light source in a good approximation, in particular for a ball lamp, and offers more possibilities of influencing the light. Furthermore, a corresponding luminous body should be specified.

This object is achieved according to the invention with a light source, which has the features mentioned in claim 1. Particular embodiments of the invention are indicated in the dependent claims.

According to the invention, a light source is provided which has a plurality of carrier elements, wherein the carrier elements each have a substantially planar surface portion, on which at least one light-emitting diode is arranged. In this case, the carrier elements are arranged relative to each other such that the surface portions of the carrier elements define the surface or part of the surface of a convex polyhedron, in particular a regular or semiregular polyhedron.

By this particular type of arrangement of the support elements can be a radiation of the luminaire achieve whose strength is very little dependent on the emission direction. It is therefore particularly suitable as a light source for a ball lamp or for the uniform illumination of the inner surface of a sphere or at least a spherical segment, such as a hemisphere. For example, it may be provided that the surface sections of the carrier elements define that part of the surface of a convex polyhedron whose surface normals are directed into a half-space. Advantageously, it is provided that the surface sections define that part of the surface of a convex polyhedron whose surface normals are directed at least into an eighth space or at least into a quarter space.

A convex polyhedron is a convex body bounded by several flat surfaces. If - in the context of the inaccuracy, which is due to the technical implementation - the planar surface portions of the support elements each lie on one of the surfaces of a convex polyhedron, they thus define the surface of this polyhedron. Manufacturing technology is easy to provide plates as support elements.

Particularly good in terms of contacting the light-emitting diodes are suitable as carrier elements circuit boards. Flexible printed circuit boards are particularly advantageous because they allow easy assembly of the support elements.

Particularly advantageously, the carrier elements are at least partially formed from a blank of a flexible printed circuit board. It can be provided, for example, that the support elements are brought by appropriate bends of the cut circuit board in the intended mutual arrangement. It can therefore be provided that at least two carrier elements are formed from a one-piece, provided with a bending circuit board, wherein the bend delimits the at least two carrier elements from each other.

It can therefore be provided that the light source is formed by a flexible printed circuit board, which forms a supporting body. The flexible circuit board may therefore be provided as a form-determining element of the light source. As a result, the guidance of the conductor tracks can be realized in an advantageous manner, in particular with regard to the electrical connection of the carrier elements to one another.

The illumination of the inner surface of a sphere can in general be made more uniform, the flatter the angles between the support elements or the respective surface portions of the support elements. However, due to the technical realization of the carrier elements, the light source is generally greater, the flatter these angles are. Therefore, if the illumination of a comparatively small spherical surface is desired, it follows that the light source must also be correspondingly small, which requires a certain minimum size for the said angle. In a light source according to the invention, a very good approximation to a point light source can be achieved by suitable adaptation between the emission angle of the LEDs and the matching diameter of the polyhedron with respect to the inner diameter of a spherical surface to be illuminated. For example, has proved for the illumination of a spherical surface with a diameter of about 120 mm is particularly suitable to choose as the underlying polyhedra form a dodecahedron. Thus, in this sense, this represents a suitable compromise between the lowest possible angles on the one hand and the smallest possible diameter of the light source on the other hand.

The support elements may in this case be designed as plates which are substantially in the form of (equally large) regular pentagons which directly represent the twelve faces of the corresponding dodecahedron. By "essentially", it should be emphasized that certain deviations in shape, in particular those due to technical reasons, are possible Such deviations in shape may, for example, be caused by connecting elements, for example by eyelets or lugs provided for mutually connecting the carrier elements.

The dodecahedron shape is suitable, for example, in the case of a light source for illuminating a sphere having a diameter of between 10 and 15 cm, for example about 12 cm, wherein the light source may have a diameter of about 45 to 50 mm. This size of the light source is sufficient (under current technical conditions) to accommodate the necessary components within the light source.

In order to enable a radiation of the light source with a particularly suitable luminance, it is advantageous to arrange on the carrier elements in each case at least two light-emitting diodes.

By way of example, RGB LEDs known per se can be used as light-emitting diodes.

For fastening and contacting the light emitting diodes on the

Carrier elements can be used advantageously the SMD technique (SMD: surface mounted device). Advantageously, the light source further comprises a drive unit for the light-emitting diodes, wherein this drive unit can be arranged on the carrier elements. The drive unit may have, for example, a PWM-IC (PWM: pulse width modulated). Further advantageously, the drive unit comprises a plurality, for example in the case of RGB LEDs three

Constant current driver, in particular constant current driver with level adjustment.

Further advantageously, the light source comprises a power supply unit for the light-emitting diodes, wherein the power supply unit is arranged on the carrier elements. The power supply unit can have a linear regulator, protective diodes and electrolytic capacitors.

Advantageously, the light source has a drive unit and a power supply unit, wherein the drive unit is arranged on a first part of the carrier elements and the power supply unit is arranged on a second, different from the first part, part of the carrier elements. This is favorable with respect to the cable connections. In particular, as a result, the number of interconnects that connect the two parts are kept particularly small; For example, it can be provided that a total of only six such connecting tracks exist between the two parts; For example, for this purpose, a first such track for the supply voltage may be provided, a second for a PWM IC, a third for "Ground", and three more for each group of LEDs of a particular color. With fewer or more colors provided, the number of corresponding tracks can be correspondingly lower or greater.

In this case, it can further be provided that the first part of the carrier elements is formed from a first blank of flexible printed circuit boards and the second part of the carrier elements from a second blank of flexible printed circuit boards.

For easy mutual connection of the support elements, these locking elements, for example in the form of eyelets and tabs have. By a locking connection formed with such locking elements, a particularly simple installation of the light source is possible; In particular, this is a montage without Tool and also without other components, such as adhesive or solder joints possible. Particularly simple and therefore advantageous, this is when the support elements are flexible circuit boards, because in this case, the locking elements can advantageously be formed only by appropriate shaping of the support elements, ie without separate components. For example, to the

Carrier elements corresponding latching openings and locking lugs or latching eyes and - lugs be formed. A manufacture of such snap-in connections is then particularly easy.

A recess for a cable feed or feedthrough can advantageously be provided between at least two carrier elements. In the case of an underlying dodecahedron, such a recess may be provided at a corner, that is, at the respective three support members through which the corner is formed, in an environment of the corner.

According to a further aspect of the invention, a luminous element is provided, which has a light source according to the invention and a substantially spherical, light-transmitting light exit body, wherein the light source is arranged in the interior of the light exit body.

According to yet another aspect of the invention, a luminous element arrangement is provided, which has at least two luminous bodies according to the invention, which are connected to one another by a common supply cable.

The invention will be explained in more detail below with reference to an embodiment and with reference to the drawings. Show it:

Fig. 1 support elements with LEDs and electronic components prior to assembly, Fig. 2, the carrier elements shown in Fig. 1, but in another

3 shows a light source assembled from the carrier elements shown in FIGS. 1 and 2, FIG. 4 shows the light source shown in FIG. 3 with the LEDs switched on, FIG. 5 an open Leeuehtkörper invention,

6 shows the luminous body shown in FIG. 5 in the closed state, FIG.

7 shows the luminous body shown in FIG. 6 with LEDs switched on, FIG.

Fig. 8 shows the luminous body shown in Fig. 7 in front of another background, and

9 is a sketch of a light source according to the invention in a state during assembly.

A light source according to the invention is shown in FIGS. 3 and 4. The light source has a plurality of, in the embodiment shown here, twelve carrier elements for light-emitting diodes (LEDs).

In Figures 1 and 2, the already equipped with LEDs 3 support elements 2 are shown prior to their assembly.

The support elements are plate-shaped, substantially the same size and each have substantially the shape of a regular pentagon. In this way, the support elements can be assembled so that their surfaces - in the context of the conditional by the technical implementation accuracy - describe a Dodekader.

9, a state is shown in sketchy form, in which the carrier elements 2 are already partially joined together, namely to two groups 10, 11 of six carrier elements 2, so that two "semi-dodecahedra" are formed which are joined together to form the light source Each of the two groups 10, 1 1 comprises a "central" carrier element 2 ', 2 ", at the five edges of which in each case a further carrier element 2 is arranged.

Due to the plate shape of the support elements, these have planar surface portions which face outward in the assembled state of the support elements 2. In each case two light-emitting diodes 3, in total 24 LEDs, are arranged on these surface sections. (For the sake of clarity, no LEDs or other further components are shown on the carrier elements 2 in FIG. 9). The light source thus formed allows for radiation, which - assuming a certain minimum distance - comes close to that of a point light source. The light source shown in this embodiment has a diameter of about 45 to 50 mm and is suitable for example for illuminating a plastic ball having an inner diameter of about 120 mm.

As LEDs RGB LEDs are selected in the embodiment, so that the color of the emitted light is adjustable.

In the exemplary embodiment, flexible printed circuit boards or a flexible printed circuit board are selected as carrier elements 2. As shown in Fig. I, the support members 2 are formed from a blank of a flexible printed circuit board. It can therefore be provided in particular that all support elements 2 are formed from only one blank; in the intended polyhedron or dodecahedron shape they can be brought, for example by appropriate bends. The arrangement sketched in FIG. 9 serves only to illustrate the geometrical conditions. In the embodiment shown in Figures 1 and 2 are - due to the blank - all support elements 2 integrally connected to each other.

The LEDs 3 are applied to the circuit boards by means of SMD technology. The flexibility of the circuit boards allows a particularly easy assembly of the support elements or a particularly easy relative alignment of the support elements with each other. The LEDs are already functional as such in the "unfolded" state shown in Figures 1 and 2. It can be provided that only the connecting wires of the LEDs are soldered and the other required electrical connections are realized by means of the printed circuit board.

The LEDs 3 (not shown in FIG. 9) on the two groups 10, 11 or "half-dodecahedra" are connected in series and the supply voltage results

48 V.

Components that serve to drive the LEDs 3, are on a first part of the support elements 2, on the first 10 of the two groups of Carrier elements 2 arranged. The drive unit has a PWM IC, as well as three constant current drivers, including level adjustment. The PWM IC is arranged on the central support element 2 'of the first group 10, on the outwardly facing surface of this support element 2'. The three components needed for the three colors are also disposed on outwardly facing surfaces of the support members 2 of this first group 10, each component on a respective other support member 2.

On a second part of the support elements 2, namely on the second group 1 1 components are arranged, which serve to power the LEDs. These components include linear regulators, protection diodes and electrolytic capacitors.

In the division of the components for the control and the power supply shown here, only six tracks are required, which interconnect the two groups 10, 11 inside the light source, for the 48 V supply voltage, 5 V for the PWM IC, Ground , as well as for the three colors red, green and blue. Connections between the outer surfaces of the carrier elements 2 carry only the currents of the three colors, so that only three printed conductors are required at this point.

The carrier elements have devices which serve for mechanical connection of the carrier elements with each other. This can be latching means, for example, eyelets and tabs, which can be locked into one another. To fix the compounds pads are provided, which can be soldered together.

For supplying a main cable in the interior of the light source recesses 15, 16 are provided in the embodiment at a corner of a group 10, 11 or at each corner of the two groups 10, 1 1 at the three surfaces in question. Advantageously, as the location of the recess in each case a corner of the central

Carrier element 2 ', 2 "provided so that the two groups 10, 11 form two constructs in the manner of a" half-shell ", and these two shells can be folded around a main cable. The electrical connection between the main cable and the carrier elements 2 is provided in the interior of the light source. In this way, unwanted shadowing by cables can be avoided.

The data transmission takes place serially via three lines, wherein a light source can be operated individually or with one or more other such light sources arranged in series on a main cable. The main cable can carry two lines for the power supply and three data lines.

FIGS. 5 to 8 each show a luminous element according to the invention. In FIG. 5, the spherical light exit body is opened, so that the light source arranged in the interior can be seen.

LIST OF REFERENCE NUMBERS

1 light source

2 support elements 2 'central support element of the first group of support elements

2 '' central support element of the second group of support elements

3 light emitting diodes

10 first group of support elements

1 1 second group of support elements 15 recess for a cable feed in the first group

16 recess for a cable feed in the second group

Claims

claims

1. Light source, comprising a plurality of carrier elements (2), wherein the carrier elements (2) each plan a substantially

Have surface portion on which at least one light-emitting diode (3) is arranged, characterized in that the carrier elements (2) are arranged relative to each other such that the upper surface portions of the support elements (2) the surface or a part of

Surface of a convex polyhedron, in particular a regular or semiregular polyhedron define.

2. Light source according to claim 1, wherein the carrier elements are plates (2).

3. Light source according to claim 1 or 2, wherein the carrier elements printed circuit boards (2), in particular flexible printed circuit boards.

4. Light source according to one of the preceding claims, wherein the support elements (2) are at least partially formed from a blank of a flexible printed circuit board.

5. Light source according to one of the preceding claims, wherein the polyhedron is a dodecahedron.

6. Light source according to one of the preceding claims, wherein on each carrier element (2) at least two light-emitting diodes (3) are arranged.

7. Light source according to one of the preceding claims, wherein the light-emitting diodes RGB LEDs (3).

8. Light source according to one of the preceding claims, wherein the light-emitting diodes (3) by means of SMD technology on the carrier elements (2) are applied.

9. Light source according to one of the preceding claims, further comprising a drive unit for the light-emitting diodes (3), wherein the drive unit is arranged on the carrier elements (2).

10. The light source of claim 9, wherein the drive unit comprises a PWM IC.

1 1. A light source according to claim 9 or 10, wherein the drive unit comprises a plurality, in particular three constant current drivers, in particular constant current driver with level adjustment.

12. Light source according to one of the preceding claims, further comprising a power supply unit for the light-emitting diodes (3), wherein the power supply unit is arranged on the carrier elements (2).

13. The light source according to claim 12, wherein the power supply unit has linear regulators, protective diodes and electrolytic capacitors.

14. Light source with the features mentioned in claims 9 and 12, wherein the drive unit is arranged on a first part (10) of the carrier elements and the power supply unit is arranged on a second, different from the first part, part (11) of the carrier elements.

15. Light source with the features of claim 4 and claim 14, wherein the first part (10) of the carrier elements from a first blank of flexible printed circuit boards and the second part (1 1) is formed by a second blank of flexible printed circuit boards.

16. Light source according to one of the preceding claims, wherein the support elements (2) are at least partially connected to each other by means of a latching connection.

17. Light source according to one of the preceding claims, wherein between at least two support elements (2) is provided a recess for a cable feedthrough.

18. A luminous body, comprising a light source according to one of the preceding claims, and a substantially spherical, translucent light exit body, wherein the light source is arranged in the interior of the light exit body.

19. filament assembly, comprising at least two luminous elements according to claim 18, by a common

Supply cable for the light sources of the two filaments are connected.