Patent Application
20240151403
The invention relates to a cooking appliance light that can be placed in a recess in the wall of a cooking appliance, in particular an oven, steam cooker, or microwave, which has,
DE 20 2019 106 170 U1, for example, discloses a cooking appliance light of this type. It is used to light the interior of such an appliance, e.g. an oven, steam cooker, or microwave. These lights must be able to withstand high temperatures. In particular in ovens, the temperatures can reach 300°. Ovens capable of pyrolysis can reach temperatures of up to 500° C.
Furthermore, fumes are generated when baking that normally contain grease and can be corrosive at high temperatures. These fumes also contain moisture, which can also be harmful. This is a major problem with steam cookers in particular, but can also be problematic with ovens and microwaves. Depending on where they are used, the lights must be able to withstand these effects, or must be sealed off effectively, particularly with steam cookers.
The use of LED light sources also requires specialized cooling. Because LED lamps are particularly sensitive to high temperatures, they must be kept as far away from the heat source as possible in the design of the cooking appliance.
Lighting the interior of the cooking appliance allows the user to observe the cooking process through the door on the appliance. This requires an effective lighting of the interior. This is particularly difficult with LED lights due to their inherent limitations. The sensitivity to high temperatures of these LED lights requires that they be kept as far away from the walls on the inside of the appliance as possible, as explained above, thus requiring that they have a comparatively long beam path. To prevent light losses between the light source and the wall of the appliance, the light emitted by the LED lights is normally conducted into the interior of the appliance using fiber optics.
The shortcoming with this technology, despite the numerous advantages, is that fiber optics are expensive. Furthermore, they must be encapsulated between the inner and outer walls of the appliance to keep them from coming in contact with the insulation therebetween. This contact would result in light losses over the length of the optical fiber.
Furthermore, the penetrations in the walls of the appliance must be tailored specifically to the use of fiber optics. This is a difficult process in the course of manufacturing the appliance, because it requires specialized tools.
The object of the invention is to therefore create a cooking appliance light that does not require fiber optics between the LED light source and the appliance walls, while still obtaining an efficient lighting of the interior of the appliance.
This problem is solved with a cooking appliance light that has the features of claim 1, in particular the characterizing features, according to which the light entry surface of the glass cap functions as a lens acting on the light coming from the light source and passing through it toward the interior of the appliance.
The cooking appliance light according to the invention takes advantage of the use of a metal sleeve, as disclosed in the prior art, which is attached to the interior wall of the appliance in a hole therein. The sleeve itself is sealed off from the appliance interior by a glass cap. This design is also used with cooking appliance lights that make use of conventional light sources, in particular incandescent lights.
The invention thus uses the sleeve as a spacer and retaining means for the LED light source. The LED light source is located at the end of the sleeve facing away from the interior wall of the appliance, and preferably secured outside of the sleeve. This allows for cooling air to flow over the LED light source, thus sufficiently cooling it.
The invention is also distinctive in that the glass cap covering the end of the sleeve is designed as a lens, in particular on its inner surface, that acts on the light exiting the glass cap, in particular diffusing it over a large surface area. This is of particular advantage if the LED light source itself has a focusing lens that focuses the light through the sleeve into the glass cap covering the end thereof. This LED lens is normally very close to the LED, i.e. directly adjacent to the LED light source.
The light entry surface on the glass cap, i.e. the optical surface thereof, is preferably concave, thus fanning out the light beams entering it.
The vertex of the concave curvature of the optical surface on the glass cap is preferably in the middle thereof, i.e. where the central longitudinal axis of the cooking appliance light passes through the glass cap.
This concave surface also extends to where the sleeve comes in contact with the glass cap. This means that the entire inner surface of the glass cap functions as a lens. It should be clear that a neck formed on the glass cap, on which a threading is formed with which it can be secured in place in the sleeve, does not form part of the lens surface.
The light emitting surface of the glass cap is preferably orthogonal to the central longitudinal axis. It can be flat or structured, in which case a structured light emitting surface can complement the function of the optically effective inner surface of the glass cap.
Further advantages of the invention are explained in the following description of exemplary embodiments of the invention.
In the drawings:
The cooking appliance light as a whole is given the reference symbol 10 in the drawings.
The cooking appliance light is shown in an exploded view in
The printed circuit board 12 has connection terminals 15 for conductors. The printed circuit board 12 is attached to a heat sink 16 by two fasteners 17. A cup-shaped mount 18 for a lens 19 in the form of a converging lens is placed downstream of the LED light source 13 in the light emission direction X.
The printed circuit board 12, heat sink 16, and converging lens 19 are contained in a retaining means 20 and secured on a sleeve 21. The retaining means 20 has legs 30, the ends of which face away from the glass cap 14 and hold the heat sink 16 in place, to which the printed circuit board 12 with the LED light source 13 is attached. The lens mount 18 and converging lens 19 are placed in the retaining means 20. The retaining means 20 also has three washer-like disks 22 that are spaced apart along the light emission direction X, thus forming ventilation gaps between them. Each successive disk 22 in the light emission direction X is slightly larger than the preceding one.
The sleeve 21 has a first end, closer to the glass cap, which has a flange 23. The wall 24 of the sleeve has notched securing blades 25. The second end of the sleeve 21, facing away from the glass cap 14, has tabs 26 extending toward the retaining means 20, each of which has a hole 27. The tabs 26 snap in place in receivers 28 formed in the retaining means 20. Each receiver 28 has a lug 29 that engages in the hole 27 in each tab 26.
The glass cap 14 has a neck 31 facing the sleeve 21. The neck 31 has an outer threading 32. The outer threading 32 interacts with the threading 33 formed in the wall 24 of the sleeve 21. This interaction between the outer threading 32 and the inner threading 33 allows the glass cap 14 to be easily screwed into the sleeve 21.
The cooking appliance light 10 is placed in a hole in the wall in a cooking appliance (not shown). The sleeve 21 is largely inside the hole, such that the flange 23 bears against the inner surface of the interior wall of the cooking appliance. The securing blades 25 bear against the rear surface of the interior wall, and secure the cooking appliance light 10 in place on the interior wall of the cooking appliance.
As can be seen in the cutaway views shown in
The light entry surface of the glass cap 14 is concave in the light emission direction X. The vertex thereof is in the middle of the glass cap 14. This center corresponds to where a central longitudinal axis that is parallel to the wall of the sleeve, passes through the glass cap. The light entry surface 34 extends outward to where the neck 31 on the glass cap 14 bears on the sleeve 21. Aside from where the outer threading 32 is formed, the entire inner surface of the glass cap 14 forms the light entry surface 34, and therefore acts as a lens surface formed by the concave structure.
The entry surface 34 diffuses the light from the LED light source 13 focused by the converging lens 19 such that an optimal lighting of the interior of the cooking appliance is obtained. The curvature of the light entry surface 34 is adjusted to the size of the cooking appliance interior for this. Based on the position of the cooking appliance light in the interior of the cooking appliance, an appropriate curvature is selected with which the light is diffused for an optimal lighting thereof. The light entry surface 34 thus forms a lens surface.
The emission surface 35 is orthogonal to the central longitudinal axis of the sleeve 21, and can also be structured for an additional diffusion effect.
The invention shows how a compact cooking appliance light 10 can be designed without complicated fiber optics, without having to make compromises with regard to cooling the LED light source 13. What is important here is that the light source unit 11 is spaced apart from the glass cap by the sleeve 21, and located outside the sleeve 21. The glass cap 14 acting as a lens is also a substantial aspect of the invention, which diffuses the light emitted by the light source unit in order to light the interior of the cooking appliance. A substantial advantage is obtained with the converging lens downstream of the LED light source 13 in the light emission direction X. This focuses the emitted light, thus significantly minimizing light losses between the LED light source 13 and the glass cap 14.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202022106278.1 | Nov 2022 | DE | national |
| 102023108263.9 | Mar 2023 | DE | national |
