LIGHTING DEVICE FOR A HOUSEHOLD APPLIANCE, AND HOUSEHOLD APPLIANCE

Abstract

A lighting device for a household appliance includes at least two light sources and a lens body which is configured at least partially to have at least two lens cones associated to the two light sources in one-to-one correspondence. Each of the lens cones has a light exit surface.

Claims

1-12. (canceled)

13. A lighting device for a household appliance, comprising: at least two light sources; and a lens body configured at least partially to have at least two lens cones associated to the two light sources in one-to-one correspondence, each said lens cone having a light exit surface.

14. The lighting device of claim 13, wherein the light exit surfaces of the lens cone abut one another in the lens body.

15. The lighting device of claim 13, wherein the light exit surfaces of the lens cone partially overlap in the lens body.

16. The lighting device of claim 13, wherein at least one of the lens cones of the lens body is embodied as a TIR (Total Inner Reflection) lens.

17. The lighting device of claim 13, wherein the lens body is made of plastic.

18. The lighting device of claim 13, wherein at least one of the at least two light sources comprises an LED (Light Emitting Diode).

19. The lighting device of claim 13, wherein at least one of the at least two light sources comprises a white light LED.

20. The lighting device of claim 13, wherein the at least two light sources output light with color temperatures which differ from one another.

21. The lighting device of claim 13, further comprising a dimmer apparatus, at least one of the at least two light sources being connected to the dimmer apparatus.

22. The lighting device of claim 21, wherein the dimmer apparatus represents a current intensity regulation unit or a pulse width modulation unit.

23. The lighting device of claim 13, wherein the lens body has boreholes on a side facing a light outlet, with one of the at least two light sources being introduced into one of the boreholes and the other one of the at least two light sources being introduced into another one of the boreholes.

24. A household appliance, comprising a lighting device, said lighting device comprising at least two light sources, and a lens body including a light outlet and configured at least partially to have at least two lens cones associated to the two light sources in one-to-one correspondence, each said lens cone having a light exit surface.

25. The household appliance of claim 24, constructed in the form of an extractor hood, said lighting device being introduced in the extractor hood so that light is output downward from the extractor hood via the light outlet.

26. The household appliance of claim 24, wherein the light exit surfaces of the lens cone abut one another in the lens body.

27. The household appliance of claim 24, wherein the light exit surfaces of the lens cone partially overlap in the lens body.

28. The household appliance of claim 24, wherein at least one of the lens cones of the lens body is embodied as a TIR (Total Inner Reflection) lens.

29. The household appliance of claim 24, wherein the lens body is made of plastic.

30. The household appliance of claim 24, wherein at least one of the at least two light sources comprises an LED (Light Emitting Diode).

31. The lighting device of claim 24, wherein at least one of the at least two light sources comprises a white light LED.

32. The household appliance of claim 24, wherein the at least two light sources output light with color temperatures which differ from one another.

33. The lighting device of claim 24, wherein the lighting device includes a dimmer apparatus, at least one of the at least two light sources being connected to the dimmer apparatus.

34. The lighting device of claim 33, wherein the dimmer apparatus represents a current intensity regulation unit or a pulse width modulation unit.

35. The lighting device of claim 24, wherein the lens body has boreholes on a side facing a light outlet, with one of the at least two light sources being introduced into one of the boreholes and the other one of the at least two light sources being introduced into another one of the boreholes.

Description

[0032] The invention is described again in more detail with reference to the accompanying drawings, in which:

[0033] FIG. 1: shows a schematic sectional view of an embodiment of the inventive lighting device;

[0034] FIG. 2: shows the beam path of the embodiment of the lighting device according to FIG. 1;

[0035] FIG. 3: shows the beam path of the embodiment in a lighting device according to the prior art; and

[0036] FIGS. 4 and 5: show schematic views from below of embodiments of the inventively used lens body.

[0037] FIG. 1 shows a schematic view of an embodiment of a lighting device 1 according to the present invention. Only the components essential to the invention are shown in the Figure. The lighting device 1 can also comprise a housing (not shown), connection lines for the power supply (not shown) and further elements for fastening (not shown) on the household appliance (not shown).

[0038] The lighting device 1 in FIG. 1 has two light sources 11, 11 and a lens body 12. The light sources 11, 11 are held on a support 10 in the embodiment shown, which can represent a printed circuit board for instance. Two lens cones 120 are formed in the lens body 12 and merge into one another. The lens cones 120 are therefore only partially formed by the exterior of the lens body 12, and merge into one another in the overlapping region 1200. The lower side of the lens body 12, which is also referred to as light outlet 121, is formed by the light exit surfaces 122 of the two lens cones 120 (see FIG. 4). Boreholes 123 are introduced into the lens body 12 in the side of the lens body 12 which is facing away from the light outlet 121. In the embodiment shown, the boreholes 123 are disposed in each case at the highest point on the first and second lens cone 120, in other words in the region of the focal point of the geometry of the lens cone 120. The light sources 11, 11 are inserted into the respective boreholes 123 in the lens body 12. The light sources 11, 11 preferably represent light sources with at least one LED.

[0039] In FIG. 2, the beam path of the light beams in the lighting device 1, in particular in the lens body 12 and below the lens body 12, is shown schematically, in particular relative to a cooker 2 which is arranged below the lighting device 1. The lighting device 1 has the structure shown in FIG. 1. It is assumed in FIG. 2 that the light source 11, which is shown on the left, is a white light LED, which outputs warm-white light, and the light source 11 which is shown on the right is a white light LED which outputs cold white light. This is indicated schematically in FIG. 2 by the different dashings of the light beams LSWW, LSKW of the two light sources 11, 11.

[0040] The light output from the light sources 11, 11 is partially reflected in the lens body 12 and output by way of the light outlet 121. Here the beam cones which leave the lens body 12 from the first and second light source 11, 11 in each case overlap below the lighting device. Since the light from the light source 11 and the light from the light source 11 has different color temperatures, a light cone L is therefore present in the region in which the two beam cones overlap, in which light is present with a uniform color temperature distribution. On account of the geometry of the lens body 12, in particular on account of the overlapping light exit surfaces 122 of the two lens cones 120, the light cone L extends to just below the lower side of the lens body 12, in other words below the light outlet 121.

[0041] The light beam L strikes the cooker 2 and covers a surface F. This surface on the cooker is lit homogeneously with light of a uniform color temperature.

[0042] The color temperature can be continuously varied between the individual LEDs in accordance with the invention and in particular in the embodiment of the lighting device according to FIG. 1 by regulating the current intensity or by using pulse width modulation (PWM) of the individual LEDs.

[0043] In FIG. 3, the beam path of the light beams is shown schematically in one of the lighting device 3 according to the prior art. The lighting device 3 here has two separate lens bodies 32 at a distance from one another. A lens cone 320 is formed by each of the lens bodies 32. In particular, FIG. 3 shows the beam path of the light beams in the two lens bodies 32 and below the lighting device 3, in particular relative to a cooker 2, which is arranged below the lighting device 3. It is also assumed in FIG. 3 that the light source 31, which is shown on the left, is a white light LED, which outputs warm-white light, and the light source 31, which is shown on the right, is a white light LED which outputs cold white light. This is indicated schematically in FIG. 3 by the different dashings of the light beams LSWW, LSKW of the two light sources 31, 31.

[0044] On account of the distance between the two lens bodies 32, with this lighting device 3 the light cone L, in which homogeneous light is present with a uniform color temperature, is smaller, in other words does not extend so close from the cooker 2 to the lighting device 3, as with the inventive lighting device 1 shown in FIG. 2. Moreover, the diameter of the light cone L on the cooker 2 is also smaller. Surface F on the cooker, which is homogeneously lit with light with a uniform color temperature, is therefore smaller.

[0045] Views from below of two embodiments of lens bodies 12 of the inventive lighting device 1 are shown in FIGS. 4 and 5. FIG. 4 shows the view from below onto the lens bodies 12 of the embodiment of the lighting device 1 from FIG. 1. As apparent from this view, the light exit surfaces 122 of the first and second lens cone 120 overlap. The dashed lines in FIG. 4 show this. However, these dashed lines are not visible on the lens body 12. The light outlet 121 formed by the light exit surfaces 122 of the lens cone 120 is instead a continuous surface. The light exit surfaces 122 overlap in an overlapping surface 1220.

[0046] FIG. 5 shows the view from below onto the lens body 12 of an embodiment of the lighting device 1, in which four lens cones are formed. The light exit surfaces 122 of the four lens cones are indicated in FIG. 5. In this context these also do not represent separate surfaces, but instead together form the light outlet 121 of the lens body 12. In the embodiment shown, two light exit surfaces 122 each overlap a further light exit surface 122 arranged therebetween in an overlapping surface 1220. Other arrangements of the light exit surfaces 122 and thus other forms of the light outlet 121 are also possible, however.

[0047] In the embodiment of the lens body 12 according to FIG. 5, the lighting device 1 has four light sources (not shown), and each of the light sources is assigned to a lens cone (not shown).

[0048] With the embodiment of the lens body 12 according to FIG. 5, a combination of a number of white light LEDs can be realized with a different color temperature in each case. In this regard, a different color temperature can be achieved depending on the switching pairing of the LEDs, so that the individual LEDs do not need to be dimmed by varying the current intensity. A simple on/off circuit of the individual LEDs would be possible as a result.

[0049] With the present invention, it is possible to produce a lighting device, which can also be referred to as white light emitter (spot), in which the light temperature can be set continuously or successively between 2700K to 6500K for instance. The impinging light is perceived homogeneously and uniformly on the lit objects/surfaces and these are illuminated in a defined manner so that the lighting device can also be used with sufficient brightness as a working light or functional light. By means of the adjustable color temperature, the lighting device, in particular the white light emitter, can be adjusted to the ambient light and is no longer perceived to be a foreign or interfering light source.

[0050] On account of the inventive structure, it is possible with simple means to design a light spot with an adjustable color temperature while simultaneously homogeneously lighting surfaces or the workspace. In order to adjust the color temperature variably, at least two white light LEDs are preferably used in accordance with the invention. In combination with the lens body, which can also be referred to as collection lens, the light of the at least two LEDs is mixed by internal reflection and focused and directed at the same time so that the light of the individual LEDs with a different color temperature on the lit surfaces is perceived to be homogeneous and single-colored.

[0051] The lit region is therefore defined and brightened uniformly. By regulating the current intensity or by changing pulse width modulation (PWM) of the individual LEDs, the color temperature can be varied continuously between the individual LEDs. With a number of LEDs with a different color temperature, the setting can also take place using a switching pairing of the LEDs.

[0052] With the inventive lighting device, the light mixture is carried out closer to the light exit surface than is the case with two separate lenses with the same focal point on the workspace. This produces a homogeneous appearance clearly in front of the surface to be lit when observed horizontally by the user.

[0053] A significant advantage of this design is that this solution can be integrated into existing LED modules.

[0054] Furthermore, the invention has the advantage of the smallest required installation height, which, in any case, is required for a lens geometry designed for the workspace to be lit.

[0055] A further plus point, in addition to the significantly smaller space requirement, is the minimal number of parts compared with complex, multistage lens optics. On account of this minimalistic design, it is possible to produce a cost-effective lighting device, which can also be referred to as spot, the individual LEDs of which can be varied by a simple current intensity change in the brightness, in order thus to achieve the desired effect of adjusting the color temperature.

LIST OF REFERENCE CHARACTERS

[0056] 1 lighting device [0057] 10 support [0058] 11 light source [0059] 11 light source [0060] 12 lens body [0061] 120 lens cone [0062] 1200 overlapping region [0063] 121 light outlet [0064] 122 light exit surface [0065] 1220 overlapping surface [0066] 123 borehole [0067] L light cone [0068] LSWW light beams warm white [0069] LSKW light beams cold white [0070] 2 cooker [0071] F homogeneously lit surface [0072] 3 lighting device (prior art) [0073] 31 light source (prior art) [0074] 31 light source (prior art) [0075] 32 lens body (prior art) [0076] 320 lens cone (prior art)