EP2207996B1 - Led lamp with diffuser - Google Patents

Description

The invention relates to an LED lamp.

A lamp is understood to mean a product in which an electrical light source is connected to further electrical, optical and / or mechanical elements to form an inseparable unit. Such a lamp is always intended only as a whole for interchangeable inclusion in a lamp.

The US 5,954,423 shows a diffuser for illuminating information signs. A row of LED elements illuminates an essentially transparent and preferably textured diffuser element which has a tent shape. In a preferred embodiment, the diffuser element is elongated and is used in conjunction with a series of LEDs mounted on a support, with posts spacing the diffuser element from the support.

In the KR-B-100762277 describes a completely closed LED lamp. An LED element is arranged inside a reflector and illuminates a semicircular cover. Structures for diffusing the light are provided on the surface of the cover.

The US 5,806,965 discloses an improved signal light with a variety of LEDs. The luminaire has a signal component, in which a large number of individual LEDs are attached to interconnected printed circuit boards in order to form an omnidirectional arrangement of LEDs.

In the US 5,655,830 describes a long-life, low-maintenance, energy-saving lighting device for connection to a socket comprising LEDs connected in a circuit.

It is the object of the invention to propose a lamp which is well suited for being received in a reflector, in particular a specular reflector. It is a further object of the invention to propose a suitable combination of a lamp and a reflector.

This object is achieved by a lamp according to claim 1 and an assembly according to claim 20. Dependent claims relate to advantageous embodiments of the invention.

The lamp according to the invention has one or more LED elements as light sources. These are attached to the lamp housing, and are preferably thermally connected to a heat sink, particularly preferably made of metal. The heat sink can be part of the lamp, but an external heat sink can also be used.

The housing has electrical and mechanical connection means. In principle, these can have any shape and are used for mechanical attachment at the place of use, for example in a luminaire, and for electrical connection to a power supply or control. Furthermore, the lamp has a light exit area which is closed with a translucent end element. The LED element itself is preferably arranged on the inside, preferably completely closed, so that no contamination or mechanical impairment is possible.

According to the invention, the termination element is an optical diffuser element. This means that it is a translucent, diffusely scattering element. Such an element can, for example, consist of a material such as glass or plastic, in which scattering particles are provided within the material (volume scattering). Alternatively, it is also possible to manufacture the body of the diffuser element itself from transparent material and only to provide scattering on its inner or outer surface, for example by appropriate surface coating, by gluing on a diffusely scattering film or by forming light-refractive surface structures, for example micro-optics, which lead to diffuse scattering. The diffuser element can be made of colored, i.e. not white material. It is also possible for the diffuser element to be coated on the inside with a phosphor which is visibly illuminated by UV excitation.

According to the invention, the end element is of a special shape, which is shown in cross section. In this form, the wall of the diffuser element in the Cross-section on two opposite, straight, converging sections. The two sections merge into each other in the further course, they meet at an apex, the intersection of the two straight lines or in a rounded transition. The wall is preferably formed in cross section at least over half its length from the straight sections, particularly preferably to more than 60%. A lamp according to the invention is particularly useful for many lighting applications:
The lamp has the outstanding properties of LED lighting in terms of long lamp life, high luminous efficacy and a large selection of light colors.

Due to the diffuse scattering on the diffuser element, the relatively high luminance levels of the LED elements are largely evenly distributed over a larger area and the luminance levels are reduced or the luminance distribution is homogenized. In this way, in particular when using differently colored LEDs, a homogeneous additive light mixture is possible.

Due to the special geometry of the diffuser, the lamp is also excellently suitable for use in a luminaire, preferably with a mirror reflector, in particular with a parabolically shaped reflector.

The straight wall sections of the end element form the diffuser element angle β in cross section to one another. As explained in connection with preferred embodiments, this angle is associated with the shielding angle α of the lamp when used in a reflector. With optimal use of the space available for lamp installation, the double lamp shielding angle 2 α and the diffuser element angle β add up to 180 °.

The diffuser element angle β can be selected on the one hand as a function of a predetermined lamp shielding angle. A diffuser element angle of 140 ° is well suited, for example, to achieve optimum utilization with a given lamp shielding angle of 20 °. Alternatively, it is of course possible, with the same, predetermined lamp shielding angle of 20 ° in the example discussed, to choose a blunt diffuser element angle β, e.g. 150 ° or 160 °. In this case, avoidance of multiple reflections would still be guaranteed, but with a somewhat poorer utilization of the maximum possible lamp volume. In general, it can therefore be said that, in order to avoid multiple reflections, it is preferred to choose the diffuser element angle β with a value of at least 180 ° -2 α for a given lamp shielding angle α, for example with a lamp shielding angle of 30 that is preferred in practice ° choose a diffuser element angle of at least 120 ° and for α = 40 ° an angle β of at least 100 °. It is therefore generally preferred not to choose the diffuser element angle too sharply, according to the invention greater than 80 °, preferably greater than 90 °.

On the other hand, in order to achieve a large lamp volume with good utilization, it is preferred to set the diffuser element angle β to not more than 140 °, more preferably to not more than 120 °, so that with good utilization, relatively high values for the lamp shielding angle α (at least 20 °, preferably 30 ° or more) can be achieved.

In two preferred embodiments, the light exit area in the top view of the lamp is either essentially round (this also includes slight deviations from the round shape, for example elliptical shapes) or essentially elongated (ie that the longitudinal extension is greater than the transverse extension, preferably that Longitudinal extension is at least 1.5 times, particularly preferably more than 2 times the transverse extension). The cross-sectional geometry according to the invention can be the same in both cases.

In the case of the lamp with an elongated light exit area, this is preferably rectangular, as seen from the main emission direction. In this case, the diffuser element is preferably cylindrical, i. H. that it has essentially the same cross section over the longitudinal extent of the lamp. For a homogeneous lamp luminance on the diffuser element, several LED individual elements or element groups (clusters) are preferably arranged one behind the other in the longitudinal direction of the lamp.

The lamp with an essentially round light exit area is preferably rotationally symmetrical, the axis of symmetry being central in the main emission direction to the final element. The end element has the shape of a cone shell, that is to say that its wall follows the shape of a cone shell at least in the area in which the straight sections are shown in cross section. In the further course the cone can taper, but it is preferred that the cone tip is rounded.

Furthermore, it is provided for the lamp with a round light exit area that the LED elements are arranged symmetrically to the main emission direction. In the case of a single LED element, this is preferably arranged exactly in the middle. Alternatively, several LED elements can be arranged in such a way that they form an essentially symmetrical arrangement, for example a 3 × 3 matrix.

• Fig. 1 eine schematische Querschnittsansicht einer ersten Ausführungsform einer LED-Diffusorlampe;
• Fig. 2 eine Draufsicht auf die Diffusorlampe aus Fig. 1;
• Fig. 3 eine perspektivische Ansicht der Lampe aus Fig. 1, 2;
• Fig. 4 eine schematische Querschnittsansicht einer zweiten Ausführungsform einer LED- Diffusorlampe;
• Fig. 5 eine Draufsicht auf die Diffusorlampe aus Fig. 4; Fig. 6 eine perspektivische Ansicht der Lampe aus Fig. 4, 5;
• Fig. 7 eine schematische Querschnittsansicht einer dritten Ausführungsform einer LED- Diffusorlampe;
• Fig. 8 eine Draufsicht auf die Diffusorlampe aus Fig. 7;
• Fig. 9 eine perspektivische Ansicht der Lampe aus Fig. 6, 7;
• Fig. 10 eine schematische Querschnittsansicht einer vierten Ausführungsform einer LED-Diffusorlampe;
• Fig. 11 eine Draufsicht auf die Diffusorlampe aus Fig. 10;
• Fig. 12 eine perspektivische Ansicht der Lampe aus Fig. 10, 11
• Fig. 13, 14, 15 Querschnittsansichten verschiedener Ausführungen von Diffusorelementen;
• Fig. 16 eine schematische Querschnittsansicht einer Leuchte mit einer Lampe gemäß der ersten Ausführungsform;
• Fig. 17 eine perspektivische Ansicht der Leuchte aus Fig. 16; Fig. 18 eine schematische Querschnittsansicht einer Leuchte mit einer Lampe gemäß der zweiten Ausführungsform; Fig. 19 eine perspektivische Ansicht der Leuchte aus Fig. 18.

Embodiments of the invention are described in more detail below with reference to drawings. The drawings show:

• Fig. 1 a schematic cross-sectional view of a first embodiment of an LED diffuser lamp;
• Fig. 2 a top view of the diffuser lamp Fig. 1 ;
• Fig. 3 a perspective view of the lamp 1, 2 ;
• Fig. 4 is a schematic cross-sectional view of a second embodiment of an LED diffuser lamp;
• Fig. 5 a top view of the diffuser lamp Fig. 4; Fig. 6 a perspective view of the lamp 4, 5 ;
• Fig. 7 is a schematic cross-sectional view of a third embodiment of an LED diffuser lamp;
• Fig. 8 a top view of the diffuser lamp Fig. 7 ;
• Fig. 9 a perspective view of the lamp Fig. 6 , 7 ;
• Fig. 10 is a schematic cross-sectional view of a fourth embodiment of an LED diffuser lamp;
• Fig. 11 a top view of the diffuser lamp Fig. 10 ;
• Fig. 12 a perspective view of the lamp 10, 11
• 13, 14, 15 Cross-sectional views of different designs of diffuser elements;
• Fig. 16 is a schematic cross-sectional view of a lamp with a lamp according to the first embodiment;
• Fig. 17 a perspective view of the lamp Fig. 16 ; Fig. 18 is a schematic cross-sectional view of a lamp with a lamp according to the second embodiment; Fig. 19 a perspective view of the lamp Fig. 18 .

Fig. 1 shows a schematic cross-sectional view of a first embodiment of a lamp 10, which in FIG Fig. 2 and Fig. 3 is shown further. This first embodiment is a compact, rotationally symmetrical LED lamp. A single LED element 12 with one LED chip or a plurality of LED chips on a circuit board is provided as the illuminant. Such LED elements with sufficient power for lighting applications are known and are therefore not explained in more detail below.

The lamp 10 has a base system 14 with a heat sink 16 and brackets 18. The heat sink 16 and the LED element 12 are firmly connected to a round base plate 22 which, together with a diffuser element 20, encloses a lamp interior 24. The elements of the lamp 10, i. H. Base system 14, LED element 12, base plate 22 and diffuser 20 are non-detachably connected to each other, for. B. by welding or gluing, so that the lamp 10 forms a unit that can only be changed as a whole. The LED element 12 illuminates the diffuser element 20 through the airtight interior 24.

The diffuser element 20 is a bowl-shaped element with translucent, diffusely scattering optical properties. As a result, the diffuser element 20 diffuses its light when illuminated by the LED element 12 and thus itself acts as a flat, secondary light-limiting element. This means that the shape of the LED element 12 as the primary light-imitating does not change from the outside Images element, but the outer shape of the diffuser element 20 is perceived as luminous. With a correspondingly non-directional radiation by the LED element 12, a relatively homogeneous luminance distribution on the diffuser element 20 results.

In the preferred example shown, the diffusely scattering properties of the diffuser element 20 are generated by volume scattering on the wall, ie the material of the diffuser element 20 has scattering particles on the inside ( Fig. 13 ). Such behavior is achieved, for example, by a material such as glass, plastic or ceramic, in which scattering particles are provided within the material.

Alternatively, it is also possible to manufacture the body of the diffuser element 20 itself from transparent material (eg glass, plastic) and to achieve diffuse scattering by the formation of surface structures, as exemplified in FIG Fig. 14 shown. It is also possible to provide a transparent diffuser element with an internally or externally applied diffusely scattering surface coating, for example a diffusely scattering film, as in FIG Fig. 15 shown. In all cases it is possible to use colored material instead of white material in order to achieve color effects with white LEDs, for example.

The lamp 10 has a light exit area, which in the example shown is formed by the area surrounding the diffuser element 20, ie the lamp 10 emits light in a largely converted manner. Nevertheless, a central optical axis O can be defined as the central axis of the light radiation, which in the example shown of a rotationally symmetrical lamp corresponds to the axis of symmetry. When viewed from a point on this axis, the light exit area of the lamp 10 appears round ( Fig. 2 ).

The diffuser element 20 is of a special external shape, which is particularly well suited for use in a reflector lamp, as shown below with the aid of Fig. 16 shown. As in the cross section of Fig. 1 The diffuser element 20 can be seen formed from two identical, symmetrically arranged sections 26 with a straight cross section and a rounded transition section 28 lying between them. The decisive factor here is the outer contour, in which shown preferred example, the diffuser element has a substantially constant wall thickness, so that the inner shape corresponds to the outer.

In the rotationally symmetrical shape shown, the outer contour of the diffuser element 20 corresponds to a truncated cone in the area of the straight sections 26, and to the rounded area 28 corresponds to a rounded tip of a cone, as in particular from Fig. 3 evident.

In the example shown, the straight sections 26 extend from the base plate 22, in the plane of which the LED element 12 is arranged. At the straight sections 26, the outer contour of the diffuser element 20 runs straight over a distance L. The straight regions 26 and the rounded transition region 28 are in this case coordinated with one another in such a way that the lengths L of the straight sections 26 preferably cover the major part, ie. H. make up over half of the contour line. The proportion can be considerably higher, for example over 60% or more than 80% as in the example shown.

The straight sections 26 run at an angle β (diffuser element angle) towards one another, so that a certain depth of the interior 24 is formed.

Fig. 16 schematically shows a lamp 30 in which the lamp 10 described above is installed. The luminaire 30 comprises a rotationally symmetrical reflector 34 in a cylindrical luminaire housing 32. At the end of the reflector, a light exit plane 36 is formed. The lamp 10 is mechanically fastened within the housing 32 with the aid of the mounting bracket 18 and electrically connected to an operating device 38 which, on the one hand, converts the supplied mains voltage into values for current and voltage required for the operation of the LED chip 12 and, on the other hand, control functions such as on - Switching off and possibly dimming (for example by appropriate modulation), color control (for example by correspondingly selective activation of differently colored LEDs with different outputs) etc.

In the cross-sectional representation of Fig. 16 can be drawn on the parabolic reflector 34 between the upper edge of the reflector and the opposite lower edge of the reflector, the lines intersecting in the middle. You define the lamp shield angle a, within which the lamp 10 with your Luminance is not directly visible from the outside and is therefore hidden. In the example of Fig. 16 the contour of the reflector 34 is a parabola with the focal point F and the apex P (or P ', opposite), ie the parabola axis is inclined at an angle of 90 ° - α to the vertical. In this case, a conical space designated by the isosceles triangle F, P, P 'is available as a lamp installation space, all light beams emitted from this space being emitted or reflected by the reflector 34 at an angle which is greater than α and therefore are hidden within the cut-off angle α outside the lamp 30. In the geometrical relationships shown, the lamp light emerges from the luminaire after only a simple reflection, multiple reflections are avoided. As in Fig. 16 the diffuser 20 of the lamp 10 is shown so that it makes good use of the available lamp installation space. The straight sections 26 run parallel to the crossing lines, forming the angle α with the base plate 22 in the example shown. This ensures that, on the one hand, the lamp 10 is only arranged within the lamp installation space (triangle F, P, P ') and, on the other hand, the available space is well utilized and the light of the LED element 12 is thereby distributed over a maximum area.

For a given angle α, the reflector height or the luminaire installation depth h is minimized while the reflector width b or the luminaire volume is minimized. The luminaire efficiency is optimized through the good utilization of the lamp installation space and the condition of the single reflection.

In the example shown, the lamp 10 has the rounded transition section 28 for manufacturing reasons. Alternatively, this section can run with a greater curvature, up to the formation of a tip, so that the outer contour of the diffuser element 20 then has a complete conical jacket shape.

The diffuser element 20 can be shaped differently for different purposes, namely have different diffuser element angles β. For example, it can be specified for the lamp 30 that a shielding angle α of 30 ° is to be achieved. How out Fig. 16 recognizable, the best possible use is made of the lamp installation space (straight sections 26 run parallel at the crossing lines) β + 2α at 180 °. That means that to achieve a Shielding angle α of 30 ° a lamp with a diffuser element angle β of 120 ° would be optimal. However, as an alternative - with a somewhat smaller lamp surface - it is of course also possible to use lamps with a less steep shape (that is to say a larger diffuser element angle β) at a given shielding angle α. Then the lamp 10 is located within the lamp installation space, but does not completely fill it, so that the straight sections 26 no longer run parallel to the crossing lines.

In practice, shielding angles α of 30 ° or 40 ° are preferred for luminaires. Here, an optimal utilization is achieved by the diffuser element angle β of 120 ° (for α = 30 °) or 100 ° (for α = 40 °).

The concept described above with reference to the compact lamp 10 can also be applied to other lamp types. So show Fig. 4 to Fig. 6 a second embodiment of a rotationally symmetrical compact lamp 110, which largely corresponds to the first embodiment of a compact lamp 10. In contrast to this, however, it is not an individual LED element that is provided, but an LED cluster 112. In the example shown, the LED cluster 112 consists of 3x3 LED elements. In this case too, the diffuser 20 serves as a secondary light source, which adds the contributions of the individual LED light sources as homogeneously as possible.

At the in Fig. 7 to Fig. 9 In the third embodiment shown, the lamp 210 shown there largely matches the compact lamp 10 in cross section Fig. 1 match. Unlike there, this is not a rotationally symmetrical lamp, but a linear lamp that extends straight in the direction of a longitudinal axis A. It has an elongated light source, which in the example shown is formed by LED elements 12 lined up in the direction of the longitudinal axis A.

The lamp 210 has a rectangular base plate 222 and a plan view of a central optical axis ( Fig. 8 ) rectangular light exit area. The end of the linear lamp 210 is mechanically fastened by means of holding bracket 218.

The diffuser 220 is cylindrical in shape, ie it has a constant shape in the direction of the longitudinal axis A. Fig. 7 Cross-sectional shape shown (that of the cross-sectional shape in the rotationally symmetrical variant, Fig. 1 , corresponds). Here too, straight sections 26 and a rounded transition section 28 are provided starting from the base plate 222. At the end, the lamp 210 is closed off by an end plate 206. A base system 214 with a heat sink and end brackets 218 is also elongated.

The linear lamp 210 can have different overall lengths. It is preferably elongated in the direction of the axis A, i. H. that their longitudinal extent is greater than their transverse extent. Possible designs are, for example, a transverse extension of 2-10 cm, preferably 5-8 cm, and longitudinal dimensions of preferably more than 10 cm, for example 30 cm or more.

The linear lamp 210 can be in a linear reflector lamp 130 as in FIG 18, 19 insert shown. Except for the elongated instead of rotationally symmetrical shape, the linear reflector lamp 130 corresponds to that in connection with FIG 16, 17 explained compact reflector lamp 30, so that here the same geometric considerations apply to a lamp installation space and its utilization. The linear reflector lamp 130 has a cylindrical linear reflector 134, which in cross section is also the same as in connection with Fig. 16 parabolic shape described. In the arrangement shown, it is ensured that the lamp light emerges from the luminaire 130 after a maximum of only one reflection on the linear reflector 134. The linear reflector lamp can be as in Fig. 19 have lamellae 140 along their length at a distance.

As a further embodiment of a lamp, in Fig.10 to Fig.12 another linear lamp 310 is shown. This largely corresponds to the third embodiment of a linear lamp 210 ( Fig. 7 to Fig. 9 ) and differs from this only in that the light source is not a single row of LED elements, but rather a 3-row cluster 312 of LED elements in the example shown.

Claims (20)

1. Lamp (10, 110, 210, 310) having

   - one or more LED elements (12),

   - and a housing with electrical and mechanical connection means, wherein the housing has a light exit region with a light-transmitting end element (20, 220),

   - wherein the end element is an optical diffuser element (20, 220),

   - and the end element (20, 220) is of a shape in which the wall of the end element (20, 220) has, in cross-section, two opposite, straight sections (26) which converge towards each other,

   - the sections (26) have an angle (β) of at least 80° to each other,

   - the housing has a base plate (22, 222) which, together with the diffuser element (20, 220), closes off an interior space (24),

   characterized in that

   - the straight sections (26) of the wall extend in cross-section from the base plate (22, 222) at an angle.
2. Lamp (10, 110, 210, 310) according to claim 1, wherein

   - the wall in cross-section at least over half of its length is formed by the straight sections (26).
3. Lamp (10, 110, 210, 310) according to one of the preceding claims, wherein

   - the sections (26) have an angle (β) of at least 90° to each other.
4. Lamp (10, 110, 210, 310) according to one of the preceding claims, in which

   - the sections (26) have an angle (13) of maximum 140°, preferably maximum 120° to each other.
5. Lamp (10, 110, 210, 310) according to one of the preceding claims, in which

   - the wall of the end element (20, 220) has a cross-sectional shape symmetrical to a central axis.
6. Lamp (10, 110, 210, 310) according to one of the preceding claims, in which

   - the LED elements (12) are arranged on a heat sink (16).
7. Lamp (10, 110, 210, 310) according to any of the foregoing claims, wherein

   - the housing is closed and the closing element (20, 220) is attached to it undetachably.
8. Lamp (10, 110, 210, 310) according to any of the foregoing claims, wherein

   - the end element (20, 220) consists of a diffusely scattering material.
9. Lamp (10, 110, 210, 310) according to any of the preceding claims 1-9, in which

   - the end element (20, 220) consists of a transparent material coated with a diffusely scattering material.
10. Lamp (10, 110, 210, 310) according to claim 10, wherein

    - the layer is glued on as a foil.
11. Lamp (10, 110, 210, 310) according to one of claims 9-10, where

    - the coating is applied to the inside of the end element (20, 220),

    - and the LED element (12) emits ultraviolet light which stimulates the coating to glow in the visible range.
12. Lamp (10, 110, 210, 310) according to any of the foregoing claims 1-7, wherein

    - the end element (20, 220) consists of a transparent material provided with a light-refracting surface structure.
13. Lamp (10, 110, 210, 310) according to one of the preceding claims, in which

    - the end element (20, 220) is made of a colored material.
14. Lamp (10, 110, 210, 310) according to one of the preceding claims, in which

    - the light-emitting area is at least substantially oblong,

    - and the end element (20, 220) is cylindrical.
15. Lamp (10, 110, 210, 310) according to claim 14, wherein

    - several LED elements (12) or LED element groups are arranged one behind the other in the longitudinal direction of the Lamp (10, 110, 210, 310).
16. Lamp (10, 110, 210, 310) according to any of the preceding claims 1 to 13, wherein,

    - the light emission area is at least essentially round,

    - and the end element (20, 220) is formed in the shape of a conical shell at least in a first region (26).
17. Lamp (10, 110, 210, 310) according to claim 16, wherein

    - the end element (20, 220) is rotationally symmetrical in the main direction of radiation with respect to a central light emission axis (O).
18. Lamp (10, 110, 210, 310) according to one of the preceding claims 16 to 17, in which

    - a plurality of LED elements (12) are arranged at least substantially symmetrically around the center of the circular light emission area.
19. Assembly comprising a lamp (10, 110, 210, 310) according to one of the preceding claims and a reflector (34, 134),

    - wherein the reflector (34, 134) is formed, and the lamp (10, 110, 210, 310) is arranged within the reflector (34, 134) such that light emitted by the lamp (10, 110, 210, 310) emerges after only single reflection and multiple reflection is avoided.
20. Assembly according to claim 19, wherein

    - the reflector (34, 134) has a shielding angle (a)

    - and the sections of the wall of the diffuser element (20, 220) of the lamp (10, 110, 210, 310) which are straight in cross-section form a diffuser element angle (β) with respect to one another,

    - where β > 180° - 2α.

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