WO2009089973A1

WO2009089973A1 - Led module having lens

Info

Publication number: WO2009089973A1
Application number: PCT/EP2008/067512
Authority: WO
Inventors: Thomas Reiners; Katrin Schroll
Original assignee: Osram Gesellschaft mit beschränkter Haftung
Priority date: 2008-01-18
Filing date: 2008-12-15
Publication date: 2009-07-23
Also published as: DE102008005120A1

Abstract

The invention relates to an LED module (1) comprising at least one carrier element (2), at least one light emitting diode (LED) (4) that is disposed on the carrier element (2), and at least one lens (5) that is disposed in the optical path of the radiation emitted by the LED. The LED module comprises at least one reflector (6), and a radiation incidence surface (10) of the lens (5) facing the LED (4) is disposed at a distance from the surface of the LED (4).

Description

Confession

LED module with a lens

Technical area

The invention relates to an LED module, comprising Minim ^¬ least one support element, at least one on the support element arranged ^¬ light emitting diode (LED) and at least one is arranged in the beam path of the radiation emitted by the LED lens.

LED chips usually emit the generated radiation relatively undirected. Therefore exhibit LED modules are arranged in element de ^¬ NEN one or more light emitting diode chips on a carrier, usually an optical system in order to adjust a defined radiation, as is desired for illumination purposes.

In its simplest form, this optical system consists of a lens, which is usually arranged on the LED chip. Frequently, this lens is made of a polymer material ^¬ because so by simple means cost ^¬ low even complex geometries can be realized Kings ^¬ nen.

There are also known solutions in which the optical system consists only of a reflector which performs the beam shaping. In order to achieve a sufficiently narrow beam angle, however, a complicated reflector geometry is necessary and the reflector has a very high overall height, which is why lens systems are preferred.

However, lenses arranged directly on the LED chip are exposed to high temperatures. This may be especially for poly ^¬ merlinsen to deterioration of optical properties Shafts and lead to a limitation of the life. With blue and white LEDs, there is still a relatively high concentration of UV radiation at the lens, which further reduces the thermal stability of most polymers and accelerates the aging of the lens.

In addition, the attachment of the lens to the LED chip, the heat dissipation is hindered by this.

Presentation of the invention

The object of the present invention is to provide an LED module comprising at least one carrier element, at least one light-emitting diode (LED) arranged on the carrier element and at least one lens arranged in the beam ^path of the light emanating from the light-emitting diode, which ^{method is} simple and inexpensive can be produced and in which the thermal load of the lens and LED chip is reduced.

This object is achieved by the LED module comprising at least one reflector and one of the LED facing radiation entrance surface of the lens is spaced from the surface of the LED. The lens is thus no longer in direct contact with the LED and the thermal stress on the components is reduced sufficiently without unduly reducing the luminous efficacy over the conventional lens assembly. Compared to the use of a reflector without a lens is a much lent more compact design allows, since the height of the reflector can be significantly reduced. In addition, a light mixture can be made via the reflector, which can also be used in the color inhomogeneities can occur on white LEDs by areas with slightly differing ^¬ cher color temperature or color, is reduced.

Advantageously, at least two LEDs are combined in a preferably rectangular group of LEDs. As a group of LED in the context of this application, at least two LED chips are considered, the distance unterein ^¬ other is less than the maximum linear dimension of the individual LED. The maximum linear dimension is the maximum distance between two points located on the outer contour of the LED. The arrangement of LEDs in groups makes it possible to realize large light outputs on a small scale.

It is desirable if a surface facing the LED radiative flat enters the lens at a distance of min ^¬ least 2.5 mm, preferably is disposed at least 5 mm, to the surface of the LED. With increasing from ^¬ stand the thermal load reduced further, which is why to prefer a distance of more than 5 mm from geringe- ren intervals.

According to an advantageous development of the invention, one of the LED facing radiation entrance surface of the lens is at a distance to the surface of the LED angeord ^¬ net, the at least the maximum linear dimension, preferably at least twice the maximum linear dimension of the LED and / or a group of LED corresponds. The maximum linear dimension while the ma ^¬ ximum distance between two located on the outer contour of the LED or the group of LED points should be considered. The arrangement according to the invention depending also obtained from the absolute size of the LED, a sufficient distance between the lens and LED to represent the function of the lens even in long-term operation sicherzu ^¬.

Furthermore, it is advantageous if one of the LED facing ^¬ radiation inlet surface of the lens is arranged at a distance from the surface of the LED, the at least a quarter of the diameter of the radiation entrance ^¬ surface of the lens, in particular at least one third of the diameter of the radiation entrance surface of the lens equivalent. Also hereby that the thermal stress of the lens is reliably reduced regardless of their absolute size and not a hit ^¬ zestau between the LED and the lens is formed is ensured.

By the LED facing radiation entrance surface of the lens at a distance of at most 30 mm, preferably ^{¬ at} least 20 mm from the surface of the LED is arranged, it is ensured that the radiation emitted by the LED radiation reaches the lens as low as possible and also a compact arrangement is achieved.

It is also advantageous if the LED facing radiation entrance surface of the lens is arranged at a distance from the surface of the LED, which is at most 8 times the maximum linear dimension, preferably at most 5 times the maximum linear dimension of the LED and / or the group of LEDs. This also ensures that, regardless of the absolute size of the LED or the group of LEDs, the radiation emitted by the LED is in sufficient concentration. tion arrives at the lens and a compact structure is achieved.

Furthermore, it is expedient if the LED facing

Radiation entrance surface of the lens is arranged at a distance from the surface of the LED, at most the

1.5 times the diameter of the radiation entrance surface of the lens, in particular at most the diameter of

Radiation entrance surface of the lens corresponds. This also ensures a compact design with good light yield.

Advantageously, the lens consisting essentially of egg ^¬ nem polymeric material is formed. Polymer Materials ermögli ^¬ chen a simple and inexpensive design, even with complex shapes, with the advantages of the invention in these lenses particularly significant impact.

It is also advantageous if the reflector surrounding the LED perpendicular to the main emission on all sides. Since ^¬ by the light yield and the efficiency is increased because all radiated light to the side in the direction of the lens or the emission can be concentrated.

It is particularly advantageous if the reflector surrounds the at ^¬ order of LED and the lens perpendicular to the main direction of radiation on all sides is. As a result, a particularly good light output and a homogeneous radiation behavior is achieved.

In an expedient development of the invention, the lens is designed as a plano-convex lens. This makes it advantageous to realize a relatively narrow beam angle of 10 ° to 30 °. In a further expedient development of the invention, the lens is designed as Konkavkonvexlinse. Since ^¬ may advantageously by a relatively wide angle of 30 ° to 60 ° can be achieved.

Furthermore, it is advantageous if at least one surface of the lens is aspherical. Aspherical lenses allow a very homogeneous radiation characteristic.

Advantageously, the edge of the lens with the optical axis encloses an angle between 10 ° and 60 °, preferably between 20 ° and 50 °. This chamfer prevents aberrations in the edge region of the lens, in which otherwise a deflection of the rays would take place in an unwanted direction. In the preferred selected from ^¬ region as many as possible of the emanating from the LED rays pass undisturbed to the reflector for given lens dimensions.

Conveniently, the LED module comprises a plurality of LEDs. Since ^¬ by the light intensity is increased and when these are summarized in ei ^¬ ner group, a compact structure aims ER.

It is expedient if the LEDs are combined in a preferably rectangular group. Such an arrangement makes it possible to install a high light output in a small space.

It is advantageous if at least one Befestigungsele ^¬ element is provided for fixing the lens to the support member. Thus the lens can be stably fixed and defi ned ^¬ distance to the likewise fixedly connected to the Trägerele ^¬ ment LED. Furthermore, it is expedient if at least one Fixed To ^¬ restriction member is provided for fixing the lens to the reflector. As a result, the lens is also held securely and formed of lens and reflector, an optical system with defined properties, which can also be handled as such and in particular also mounted.

A particularly simple construction is obtained when Minim ^¬ least one fastening element and the lens are integrally formed. In addition, these can then be produced and processed together, which simplifies the manufacturing process of the module.

Furthermore, it is expedient if the fastening element has at least one snap connection for connection to the reflector and / or the carrier element. As a result, a connection can be established in a simple way, and thus the manufacturing outlay for the LED module can be reduced.

It is advantageous if the reflector comprises a plurality of annular segments. While those areas of the reflector are seen in emission direction as segments be ^¬ seeks within which the direction of curvature in the optical axis of the reflector section containing ^¬ remains planar same, wherein the segments from each other by a Wech ^¬ sel the direction of curvature, or a sudden change in the curvature are delimited. Due to the segmentation, the radiation behavior can be advantageously influenced since the individual ring segments can each reflect in different directions. This is especially useful for better color homogeneity. LEDs or groups of LEDs with different color or color temperature.

It is also advantageous if at least one segment of the reflector has at least 6, preferably between 10 and 14, in particular 12 facets. The faceting causes a further homogenization of the color distribution, since this overlaps the images of different areas of an LED chip or different LED of a group of LEDs.

Furthermore, it is expedient if the reflector is essentially formed of a thermally highly conductive material, in particular aluminum. This allows the reflector to be used in addition to the heat dissipation of the LED and

Short description of the drawing (s)

In the following, the invention will be explained in more detail with reference to an embodiment ^¬ example. The figure shows a he ^¬ inventive LED module in a side sectional Bilddarsteilung.

Preferred embodiment of the invention

The LED module 1 essentially comprises a support plate 2, on which according to the invention a group 3 of light-emitting diodes (LED) 4, as well as a lens 5 and a reflector 6 are angeord ^¬ net. The center of group 3 of LEDs 4 is located as well as the central axis of the lens 5 and the central axis of the reflector 6 on the optical axis A of the overall system.

The support member 2 is carried out in the present exemplary embodiment as a game board 2 on which a group 3 of a total of six light emitting diode chip 4, is befin ^¬ det. These are arranged in two rows of three rectangular individual chips 4, so that there is a rectangular overall arrangement with an edge length of about 3 mm in the longitudinal direction and about 2 mm in the transverse direction. The considered LEDs 4 emit radiation in the visible light range.

The lens 5 is made of a transparent polymer material according to the prior art and at a distance of approximately 8 mm from the group 3 of light-emitting diodes 4 via fastening means 7 with the carrier element 2 verbun ^¬ the. The distance of the lens 5 from the group 3 of LED 4 is thus more than 2 times the maximum linear dimension of the group 3 of LED 4, which in this case is the diagonal of the rectangular array of about 3.6 mm. Too large a distance of the lens 5 from the LED 4 should be avoided, since thus the thermal Be ^¬ load of the lens 5 continues to decrease, but the arrangement is then very large. A maximum distance of 20 mm or approximately 5 times the maximum linear extent of group 3 of LED 4 has proven to be expedient for the components usually used. The fastening means 7 have snap lugs 8 at their end facing the printed circuit board, which engage in bores 9 in the carrier element 2 and thus produce a snap connection. The lens 5 has a diameter of approximately 17 mm and is designed as aspherical plano-convex lens, which allows a narrow beam angle of about 20 °. The distance of the radiation entrance surface 10 of the lens 5 is thus arranged at a distance from the surface of the LED 4, which corresponds to more than one third of the diameter of the radiation entrance surface 10 of the lens 5, in the present example, even approximately half. Too large a distance from the lens 5 and LED 4 would require a very large lens diameter to an equal proportion of the emitted light with the lens 5 to he ^¬ take as in a nearer to the LED 4 lens 5. However, this increases the manufacturing effort and the LED module 1 becomes very large and unwieldy. It has proved to be advantageous to choose the distance from the radiation entrance surface 10 of the lens 5 and LED 4 smaller than the lens diameter.

By the aspherical shape of the lens 5 is a very ho ^¬ mogenous emission is achieved. In addition, the edge region 11 of the lens 5 is inclined relative to the optical axis A at an angle of approximately 22 °, which imaging ^¬ error is reduced in the edge region of the lens 5 or prevented by as few as possible of the radiation, the lens 5 in this for the imaging characteristics unfavorable area.

In order to be able to exploit the light rays emerging laterally from the lens 5 for the illumination of the area to be illuminated, the LEDs 4 are perpendicular to the main ^¬ radiation, which is identical in the embodiment with the optical axis A, surrounded on all sides by the reflector 6. The reflector 6 is composed of several Rings 6a, 6b, 6c together, which have a plurality of non-recognizable in this representation facets, for example between 10 and 25, have. In the main emission direction, the reflector 6 extends beyond the lens 5 in order to direct the largest possible portions of the radiation into the area to be illuminated. Especially the middle and outer angular ranges of the Abstrahlcha ^¬ rakteristik be covered. The faceting allows mixing of light emitted from different regions of the group 3 of LED 4 light so that a ho ^¬ seamless front light radiation with uniform distribution of the color as well as the color temperature can be achieved, even if the both within the LEDs 4 as well as between the individual LEDs 4 differences exist.

The reflector 6 is made of an aluminum alloy, whereby it can be used for heat dissipation from the LEDs 4. On the inside it is provided with egg ^¬ ner suitable reflective coating.

The reflector 6 is fixed by means of suitable fasteners according to the prior art on the support element 2. It is also conceivable, for example, for the ^fastening elements 7 of the lens 5 to be used for this purpose. Furthermore, other embodiments of the reflector 6 are conceivable, for example, by this consists of only one ring 6a or cylindrical is executed without facets. The height can be different than in Ausführungsbei ^¬ game, in particular lower, are selected. For example, it is conceivable that the reflector 6 extends only to the upper edge of the lens 5 or even only to the radiation entrance slit 10. The fastening elements 7 of the lens 5 may additionally or alternatively also be fixed to the reflector 6, for example also by extending laterally from the lens 5 to the reflector 6. Thus, the unit of lens 5 and reflector 6 can be mounted in the production as a common, which facilitates the production. Depending on the circumstances, it is also conceivable that the lens 5 and reflector ^¬ gate 6 are made in one piece of a transparent polymer material and the reflector 6 is then provided on its inner side with a reflective coating.

The shape of lens 5 and reflector 6 depends essentially on the shape of the LED 4 and the group 3 of LED 4 and the desired radiation characteristics. Thus, an approximately circular radiating ^¬ characteristic is achieved in the illustrated embodiment from a right square ^¬ light source. Likewise, the distance between the edge 11 of the lens 5 and the reflector 6 can be selected depending on the application, in order to determine the distribution between the ^{proportion of} the light passing through the lens 5 and the light passing ^therethrough . Under certain circumstances, this distance can also be important for the cooling of the LED and, depending on the application, should therefore not be less than a minimum ^dimension .

Depending on the desired characteristic, it is of course also possible to use another lens 5 or even a combination of lenses instead of the plano-convex lens 5. In particular Konkavkonvexlinsen are suitable if a relatively wide beam angle of about 30 ° to 60 ° to be achieved.

Claims

claims

1. LED module (1) comprising at least one carrier element (2), at least one on the carrier element (2), ^¬ arranged light-emitting diode (LED) (4) and at least one arranged in the beam path emanating from the LED radiation lens (5) , characterized in that the LED module comprises at least one reflector (6) and one of the LED (4) facing the radiation entrance surface ^¬ (10) of the lens (5) from the surface of the LED (4) is arranged spaced.

2. LED module (1) according to claim 1, characterized in that at least two LED (4) in a preferential ^¬ rectangular group (3) of LED (4) are summarized summarized.

3. LED module (1) according to claim 1 or 2, characterized in that the LED (4) facing the radiation ^¬ entry surface (10) of the lens (5) at a distance of at least 2.5 mm, preferably from at least 5 mm, to the surface of the LED (4) is arranged.

4. LED module (1) according to one of claims 1 to 3, character- ized in that the LED (4) facing

Radiation entrance surface (10) of the lens (5) is arranged at a distance from the surface of the LED (4), the at least the maximum linear dimension, preferably at least twice the maximum linear dimension of the LED (4) and / or the group ( 3) of LED (4).

5. LED module (1) according to one of claims 1 to 4, since ^¬ characterized in that the LED (4) facing the radiation entrance surface (10) of the lens (5) arranged at a distance from the surface of the LED (4) is at least a quarter of the diameter of the radiation entrance surface (10) of the lens (5), in particular ^¬ special at least one third of the diameter of the radiation entrance surface (10) of the lens (5) ent ^¬ speaks.

6. LED module (1) according to one of claims 1 to 5, since ^¬ characterized in that the LED (4) facing the radiation entrance surface (10) of the lens (5) at a distance of at most 30 mm, preferably from hochs ^¬ at least 20 mm from the surface of the LED (4).

7. LED module (1) according to one of claims 1 to 6, since ^¬ characterized in that the LED (4) facing the radiation entrance surface (10) of the lens (5) arranged at a distance from the surface of the LED (4) is equal to at most 8 times the maximum linear dimension, preferably at most 5 times the ma imum ^¬ linear dimension of the LED (4) and / or the group (3) of LEDs (4).

8. LED module (1) according to one of claims 1 to 7, character- ized in that the LED (4) facing

Radiation entrance surface (10) of the lens (5) is arranged at a distance from the surface of the LED (4) which is at most 1.5 times the diameter of the radiation entrance surface (10) of the lens (5), in particular special maximum corresponds to the diameter of the radiation entrance surface (10) of the lens (5).

9. LED module (1) according to one of claims 1 to 8, since ^¬ characterized in that the lens (5) is formed essentially of a polymer material.

10. LED module (1) according to one of claims 1 to 9, since ^¬ characterized in that the reflector (6) surrounding the LED (4) perpendicular to the main radiation on all sides.

11. LED module (1) according to one of claims 1 to 10, characterized ^{¬ in} that the reflector (6) surrounds the order ^¬ of LED (4) and lens (5) perpendicular to the main radiation on all sides

12. LED module (1) according to one of claims 1 to 11, character- ized in that the lens (5) is designed as Plankon ^¬ vexlinse (5).

13. LED module (1) according to one of claims 1 to 11, since ^¬ characterized in that the lens (5) is designed as a concave ^¬ convex lens.

14. LED module (1) according to one of claims 1 to 13, since ^¬ characterized in that at least one surface of the lens (5) is formed aspherical.

15. LED module (1) according to one of claims 1 to 14, since ^¬ characterized in that the edge of the lens (5) with the optical axis A includes an angle between 10 ° and 60 °, preferably between 20 ° and 50 °.

16. LED module (1) according to one of claims 1 to 15, since ^¬ characterized in that the LED module (1) comprises a plurality of LED (4).

17. LED module (1) according to one of claims 1 to 16, characterized in ^{¬ ¬} characterized in that at least one fastening ^¬ transmission element (7) for fixing the lens (5) on the support element (2) is provided.

18. LED module (1) according to one of claims 1 to 17, characterized in ^{¬ ¬} characterized in that at least one fastening ^¬ transmission element (7) for fixing the lens (5) on the reflector (6) is provided.

19. LED module (1) according to one of claims 1 to 18, character- ized in that at least one fastening ^¬ tion element (7) and the lens (5) are integrally formed ^¬ forms.

20. LED module (1) according to one of claims 1 to 19, since ^¬ characterized in that the fastening element (7) has at least one snap connection for connection to the reflector (6) and / or the carrier element (2).

21. LED module (1) according to one of claims 1 to 20, since ^¬ characterized in that the reflector (6) at least two annular segments (6a, 6b, 6c).

22 LED module (1) according to one of claims 1 to 21, since ^¬ characterized in that at least one segment

(6a, 6b, 6c) of the reflector (6) at least 6, before ^¬ th preferably 10 to 14, in particular 12 has facets.

23. LED module (1) according to one of claims 1 to 22, as ^¬ characterized by that the reflector (6) is formed in ^¬ We sentlichen of a thermally well-conducting material, in particular aluminum.