LED retrofit lamp and cooling element for a LED retrofit lamp

Abstract

A light fixture comprises two cooling elements and a plurality of semiconductor lighting elements, wherein each cooling element has a central portion and a wall portion which extends away from the central portion and at least partially surrounds an interior of a cooling element. The two cooling elements are arranged opposite one another. An annular opening for exchange of air with the environment is present between the two cooling elements. The semiconductor lighting elements are arranged on the outside of the wall portion of the cooling elements. A corresponding cooling element has two or more vanes, wherein all vanes are connected to one another by means of a central connecting element. Each vane extends in an axial direction and in a circumferential direction and has a curvature in the axial direction and preferably a curvature in the circumferential direction.

Claims

1. A light fixture comprising: two cooling elements; and a plurality of semiconductor lighting elements; wherein each cooling element has a central portion and a wall portion which extends away from the central portion and at least partially surrounds an interior of a cooling element, characterized in that the two cooling elements are arranged opposite one another, in that the two cooling elements are arranged so that an annular opening is present between them, and in that the semiconductor lighting elements are arranged on the outside of the wall portions of the cooling elements.

2. The light fixture according to claim 1, wherein the two cooling elements have an identical structure.

3. The light fixture according to claim 1, wherein the cooling elements are produced from heat-conducting plastic.

4. The light fixture according to claim 1, further comprising an electronic driver for controlling the semiconductor lighting elements, wherein the electronic driver is arranged in the interior of at least one of the two cooling elements.

5. The light fixture according to claim 1, further having at least two translucent covers, which in each case extend over at least a part of the plurality of semiconductor lighting elements.

6. The light fixture according to claim 1, wherein each wall portion has two or more vanes, wherein the central portion is a central connecting element, wherein all vanes of a cooling element are connected to one another by means of the central connecting element, wherein each vane extends in an axial direction, and wherein each vane has a curvature in the axial direction.

7. The light fixture according to claim 6, wherein each vane extends in a circumferential direction, and wherein each vane has a curvature in the circumferential direction.

8. A cooling element for a light fixture, the cooling element having two or more vanes, wherein all vanes are connected to one another by means of a central connecting element, and wherein each vane extends in an axial direction, characterized in that each vane has a curvature in the axial direction.

9. The cooling element according to claim 8, wherein each vane extends in a circumferential direction, and wherein each vane has a curvature in the circumferential direction.

10. The cooling element according to claim 9, wherein each vane has a first portion in the shape of a truncated pyramid and a second portion in the shape of a truncated pyramid adjoining the first portion in the shape of a truncated pyramid, wherein the second portion in the shape of a truncated pyramid is connected to the central connecting element, wherein generated surfaces of the first portion in the shape of a truncated pyramid enclose a first angle with the axial direction and generated surfaces of the second portion in the shape of a truncated pyramid enclose a second angle with the axial direction, and wherein the first angle is different from the second angle.

11. The cooling element according to claim 8, wherein each vane has two or more longitudinal portions, wherein each longitudinal portion has two or more part-portions, and wherein each part-portion is arranged at an angle to the adjacent part-portions.

12. The cooling element according to claim 8, wherein each two vanes are arranged spaced apart from one another in the circumferential direction.

13. The cooling element according to claim 8, wherein each vane is connected to the central connecting element by means of a plurality of connecting struts.

14. The cooling element according to claim 8, wherein each vane has a plurality of cooling ribs on the inside of the vane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred further embodiments of the invention are explained in greater detail by the following description of the drawings. In the drawings:

(2) FIG. 1 shows a schematic representation of an embodiment of a cooling element according to the invention;

(3) FIG. 2 shows a schematic representation of an embodiment of a light fixture according to the invention in a lateral sectional view;

(4) FIG. 3 shows a schematic representation of an embodiment of a light fixture according to the invention in a perspective, partially cut-away view; and

(5) FIG. 4 shows a comparison of the light distribution of a HQL lamp with the light distribution of a light fixture according to the invention.

DETAILED DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS

(6) Preferred exemplary embodiments are described below with reference to the drawings. In this case elements which are the same, similar, or act in the same way are provided with identical reference numerals in the different drawings, and repeated description of some of these elements is omitted in order to avoid redundancies.

(7) In FIG. 1, an embodiment of a cooling element according to the invention is illustrated schematically in plan view. The cooling element has a wall portion with three vanes 1, which are in each case connected every by means of a plurality of connecting struts 2 to an annular central connecting element 3 (central portion). Between each two adjacent connecting struts 2 of a vane 1, there is an opening 4 that serves for exchange of air between the interior of the cooling element and the environment.

(8) Each vane 1 comprises a plurality of longitudinal portions 5. In each case, six longitudinal portions 5 per vane 1 are illustrated in the drawings, but a different number of longitudinal portions can also be used, for example 3, 4, 5, 7, 8, etc.

(9) Each of the longitudinal portions 5 in turn comprises a plurality of part-portions 6. Six part-portions 6 per longitudinal portion 5 are illustrated in the drawings, but a different number of part-portions can also be used, for example 3, 4, 5, etc.

(10) The cooling element is produced from a heat-conducting plastic in an injection moulding process. This means that the longitudinal portion 5 and the part-portions 6 are not separate elements which are combined to form a vane, but constitute logical portions of a vane.

(11) In each case, two adjacent part-portions 6, which are substantially planar when viewed individually, are arranged at an angle relative to one another so that each vane has a double curvature, i.e. a curvature in circumferential direction U because of the angle between the longitudinal portions 5 or the adjacent part-portions 6 in the circumferential direction as well as a curvature in the axial direction A (perpendicular to the drawing plane in FIG. 1) because of the angle between the part-portions 6 in each case of a longitudinal portion 5.

(12) Each vane 1 extends in the circumferential direction U over approximately 110. As a result, a spacing 7 of approximately 10 remains between each two vanes 1. This spacing 7 allows the exchange of air between the interior of the cooling element and the environment.

(13) Each vane 1 of the illustrated embodiment can also be described so that the vane 1 consists of two portions in the shape of truncated pyramids. In this case, each portion in the shape of a truncated pyramid constitutes a cutout of approximately 110 out of a truncated pyramid of a polyhedral pyramid. An inner portion in the shape of a truncated pyramid is fastened by means of the connecting struts 2 on the central connecting element 3. The outer surface of the inner portion in the shape of a truncated pyramid encloses an angle of approximately 25 with the axial direction.

(14) The inner portion in the shape of a truncated pyramid adjoins an outer portion in the shape of a truncated pyramid. The outer surface of the outer portion in the shape of a truncated pyramid encloses an angle of approximately 8 with the axial direction.

(15) Of course, the angle details given above are only provided by way of example. Other values can also be used.

(16) An embodiment of a light fixture according to the invention is shown schematically in a lateral sectional view in FIG. 2. The same embodiment is illustrated schematically in FIG. 3 in a perspective, partially cut-away view.

(17) The light fixture according to the invention has a base 8 (for example an Edison screw base of the E40, E27 type or the like), which is connected to a tubular driver housing 9. The driver housing 9 extends in the axial direction substantially over the entire length of the light fixture. The electronic driver (not shown) of the light fixture can accommodated in the driver housing. The driver housing is preferably manufactured from an electrically insulating material.

(18) As illustrated in FIG. 1, two cooling elements are connected to the driver housing 9. A cooling element on the base side extends from the end of the driver housing 9 on the base side to approximately the centre thereof. A cooling element remote from the base extends from the end of the driver housing 9 remote from the base side likewise to approximately the centre thereof. A spacing 10 which remains between the ends of the cooling elements in the centre of the light fixture serves for the exchange of air between the interior of the light fixture and the environment.

(19) Cooling ribs 11, which extend to the driver housing 9, can be seen on the inside of the vane 1. A cooling rib 11, which serves in each case as a connecting strut 2 between the longitudinal portion 5 and the central connecting element 3 or merges into the connecting strut 2, is provided for each longitudinal portion 5.

(20) Flexible circuit boards 12, on which LEDs 13 are arranged as semiconductor lighting elements arranged on the outside of the vanes 1. A circuit board 12 is provided for each longitudinal portion 5. Cable feedthroughs (not shown) can be provided in the vanes for the electrical connection between the circuit boards 12 and the driver.

(21) On each longitudinal portion, the LEDs 13 on the outside are arranged opposite the cooling ribs 11 on the inside. This produces the shortest possible thermal path from the LEDs 13 to the cooling ribs 11, which is advantageous for thorough heat removal.

(22) A translucent cover 14 (in particular one with a diffuse scattering effect) is provided for each vane 1, and in each case a cover is connected to the vane 1 by means of latching elements (not shown). The translucent cover 14 provides protection of the LEDs 13 against external influences, which may be of interest particularly outdoors, in particular when the light fixture is used in a luminaire which offers no additional protection.

(23) The distances 7, 10 between the vanes and between the cooling elements are not closed (at least not completely) by the transparent covers 14, so that furthermore an exchange of air between the interior of the light fixture and the environment is possible.

(24) This open construction of the light fixture according to the invention ensures that the temperature of the LEDs remains within the permitted parameters regardless of the installation position (horizontal or vertical).

(25) The light fixture described here according to the invention has a compact construction, the dimensions of which only slightly exceed (by a maximum of 10%) the dimensions of a HQL or NAV light fixture with the same illumination intensity which is to be replaced. The light fixture according to the invention can therefore be used as a retrofit lamp in many already existing lights.

(26) By the use of a large number of LEDs (optionally with reduced output) and the uniform distribution thereof over the entire outer surface of the lamp, the light fixture according to the invention has, in the near field, a similar emission characteristic to the HQL and NAV light fixture to be replaced (i.e. the entire outer surface of the light fixture illuminates, similar to the outer surface of the bulb in the case of the light fixtures to be replaced).

(27) The homogeneity of the illuminating surface can be further improved by the use of a cover with a diffuse scattering effect over the LEDs. Moreover, the curvature of the vanes and therefore of the circuit board attached thereto makes it possible to provide sufficient light in the forward and backward direction. The emission characteristic of the light fixture according to the invention in the far field is in turn very similar to that of the HQL and NAV light fixture to be replaced. This can be seen in FIG. 4 which shows, on the left, the measured light distribution of a conventional HQL lamp and, on the right, the simulated light distribution of a light fixture according to the invention. Thus, the almost identical emission characteristic of the light fixture ensures that with the light fixture according to the invention the light distribution of a luminaire is maintained in accordance with standards.

(28) Although the invention has been illustrated and described in greater detail by the depicted exemplary embodiments, the invention is not restricted thereto, and other variations can be deduced therefrom by the person skilled in the art without departing from the scope of protection of the invention.

(29) In general, a or an may be understood as a single number or a plurality, in particular in the context of at least one or one or more etc., provided that this is not explicitly precluded, for example by the expression precisely one etc.

(30) Also, when a number is given this may encompass precisely the stated number and also a conventional tolerance range, provided that this is not explicitly ruled out.

(31) If applicable, all individual features which are set out in the exemplary embodiments can be combined with one another and/or exchanged for one another, without departing from the scope of the invention.

LIST OF REFERENCES

(32) 1 vane

(33) 2 connecting struts

(34) 3 central connecting element

(35) 4 openings

(36) 5 longitudinal portions

(37) 6 part-portions

(38) 7 spacing between two vanes

(39) 8 base

(40) 9 driver housing

(41) 10 spacing between cooling elements

(42) 11 cooling ribs

(43) 12 circuit boards

(44) 13 LEDs

(45) 14 translucent cover

(46) A axial direction

(47) U circumferential direction