The present invention relates generally to a domestic refrigerator having a wall lighting module which is fitted into a wall surface of a cold chamber of the refrigerator.
Domestic refrigerators frequently have one or more lighting devices by means of which the interior of the refrigerator, which serves to keep foods cold, is illuminated when the door is open so that a user is better able to see the foods stored therein. For aesthetic reasons, suitable lighting modules are sometimes fitted into a (e.g. side or back) delimiting wall of the cold chamber, so that the user perceives the lighting module as an integral part of the wall surface. Because of their luminous power and working life, light-emitting diodes have become increasingly important as the type of light source used in lighting devices for domestic refrigerators. However, the fact that the luminous power of light-emitting diodes is concentrated at a point can give rise to the problem that the user perceives the brightness as being unevenly distributed over the light outlet surface of the lighting module.
Accordingly, it is an object of the invention to provide a domestic refrigerator equipped with a wall lighting module in which a good luminous intensity of the lighting module can be achieved with as homogeneous as possible a distribution of the brightness.
In order to achieve that object there is provided according to the invention a domestic refrigerator having a cold chamber delimited by walls, and at least one lighting module inserted into a wall opening of a delimiting wall of the cold chamber. The lighting module includes a planar, transparent light outlet pane arranged parallel to the delimiting wall and having a transmittance of not less than 90% in the visible spectrum; a frame, inserted into the wall opening, for holding the light outlet pane, wherein the frame, on the side of the delimiting wall facing the cold chamber, overlaps the opening edge all around the wall opening and the light outlet pane is inserted into the frame inside the contour of the wall opening, wherein the light outlet pane, on its pane side remote from the cold chamber, rests along its pane periphery on a support shoulder formed by the frame; a light source arrangement having at least one light-emitting diode, wherein, in a projection perpendicular to the pane plane of the light outlet pane, each light-emitting diode of the light source arrangement is arranged so that it is concealed; and a light reflection surface, arranged behind the light outlet pane and irradiated by each light-emitting diode of the light source arrangement, for reflecting light in the direction towards the light outlet pane, wherein the light reflection surface, in a region that is visible through the light outlet pane when viewed perpendicularly to the pane plane, has all over a roughness depth Rz of not less than 2.5 μm and not more than 8.0 μm and an arithmetical mean roughness value Ra of not less than 0.63 μm and not more than 2.4 μm. In some embodiments, the roughness depth Rz of the light reflection surface is not less than 3.0 μm and not more than 6.5 μm, while the arithmetical mean roughness value Ra is not less than 0.8 μm and not more than 2.0 μm.
Owing to the high transmittance of the light outlet pane of at least 90% and in some embodiments of at least 93% or even at least 95%, losses in luminous intensity, as would be feared, for example, in the case of a satinised or milky form of the light outlet pane, can be avoided. At the same time, the roughness of the light reflection surface with the indicated numerical values of the roughness depth Rz and the arithmetical mean roughness value Ra ensure good homogeneity of the brightness distribution which a user perceives when he looks at the light outlet pane. In the solution according to the invention, the light reflection surface is not a high gloss polished surface and can be adjusted to the desired roughness by an electrical discharge machining process, for example. Where mention is made in the context of the present disclosure of the roughness depth Rz, it is understood as being the mean roughness depth Rz defined in standard DIN EN ISO 4287, while the arithmetical mean roughness value Ra means the corresponding parameter defined in the same standard. With the indicated numerical values of the roughness depth Rz and the arithmetical mean roughness value Ra, the light reflection surface has a diffusely reflecting action and in particular acts almost in the manner of a Lambertian radiator. This property of the light reflection surface ensures sufficient homogenisation of the brightness distribution on the light outlet side of the light outlet pane. Moreover, the concealed arrangement of each light-emitting diode of the light source arrangement makes it possible to prevent the user from looking directly at the light-emitting diode(s) when he looks at the light outlet pane perpendicularly, and a visually perceptible inhomogeneity in the brightness distribution can thus be avoided.
In some embodiments, the frame has holding structures by means of which it can be clamped between mutually opposite edge regions of the wall opening, wherein the holding structures comprise at least one resiliently deflectable clamping tongue which in a tongue end region has a stepped profile with a plurality of steps, wherein the clamping tongue is in clamping engagement with the delimiting wall at only one of the steps. The different steps of the stepped profile permit adaptation to different thicknesses of the delimiting wall, that is to say the clamping tongue can be in clamping engagement with the delimiting wall at a different step according to the wall thickness of the delimiting wall. It is then not necessary to manufacture a different model of the frame for different refrigerator models which differ by a different wall thickness of the delimiting wall. Instead, a universal frame which is compatible with different thicknesses of the delimiting wall can be provided.
In some embodiments, the frame is equipped with holding structures for holding the lighting module on the delimiting wall, wherein the holding structures permit an insertion movement, oriented transversely to the wall plane of the delimiting wall, of the lighting module into the wall opening, followed by a locking movement, oriented parallel to the wall plane of the delimiting wall, of the lighting module. The holding structures can thereby comprise at least one resiliently deflectable pressing element which passes through the wall opening during the insertion movement of the lighting module and moves under the delimiting wall during the locking movement of the lighting module. The pressing element can delimit a clamping slot into which the delimiting wall moves during the locking movement of the lighting module. For example, the pressing element is formed by a spring leaf which is clamped at both ends. The lighting module can be adapted to different thicknesses of the delimiting wall also in the case of the embodiments that comprise a resiliently deflectable pressing element, namely by deflecting the pressing element to different degrees.
In some embodiments, the light reflection surface and at least a portion of the support shoulder are formed by a common white plastics injection-moulded body. In some embodiments, this white plastics injection-moulded body can form the entire frame including a frame region which protrudes from the opening edge of the wall opening on the side of the delimiting wall facing the cold chamber. In other embodiments, the frame can comprise a frame part extending all round the light outlet pane, which frame part is of a contrasting colour to the white plastics injection-moulded body and protrudes from the opening edge of the wall opening on the side of the delimiting wall facing the cold chamber. By means of such a frame part, which forms a separate component from the white injection-moulded body, a particularly elegant form of the lighting module can be achieved with a suitable colour choice.
In some embodiments, each light-emitting diode of the light source arrangement is arranged with its main beam axis at such an angle to the pane plane of the light outlet pane that all the light of the light-emitting diode in question that is transmitted through the light outlet pane undergoes an at least one-time reflection at the light reflection surface beforehand, where the light reflection surface, when viewed in a section normal to the pane plane and containing the main beam axis of the light-emitting diode, extends at least in part in a curved manner between a first end region, which is situated closer to the light-emitting diode and further away from the light outlet pane, and a second end region, which is situated further away from the light-emitting diode and closer to the light outlet pane.
The present invention additionally provides a group of domestic refrigerators in which the frame of the lighting module in each case has holding structures by means of which the frame can be clamped between mutually opposite edge regions of the wall opening, where the holding structures include at least one resiliently deflectable clamping tongue which in a tongue end region has a stepped profile with a plurality of steps, wherein the clamping tongue is in clamping engagement with the delimiting wall at only one of the steps. The domestic refrigerators of the group differ from one another by a different wall thickness of the delimiting wall in the region of the wall opening, where in each of the domestic refrigerators of the group, the clamping tongue is in clamping engagement with the delimiting wall at a different step of the stepped profile.
The invention will be explained in greater detail below with reference to the accompanying drawings.
Reference will first be made to
When the door 24 is open (as is shown in
At least one of the wall lighting modules 26 can have the form shown in
The light outlet pane 30 is set flush into the frame 36, so that the pane front side of the light outlet pane 30 facing the cold chamber 22 of the refrigerator 10 merges substantially continuously into the adjoining regions of the frame front side of the frame 36. It will be seen in
Each light-emitting diode 34 is arranged so that it is concealed by the module housing 28, such that an observer, when looking perpendicularly to the pane plane of the light outlet pane 30, does not have a direct view of the light-emitting diodes 34. In the example shown, the light-emitting diodes 34 are arranged with their main beam axis (denoted 48) substantially parallel to the pane plane of the light outlet pane 30. The main beam axis 48 is the axis on which the emission pattern of the light-emitting diode 34 in question has the greatest radiation intensity. Typically, the emission pattern of each light-emitting diode 34 has a main lobe with an opening angle of, for example, more than 90° or more than 120° or more than 150°, it being possible in some circumstances for one or more side lobes additionally to be present. In other embodiments, the circuit board 32 can be at an angle relative to the pane plane of the light outlet pane 30, namely in such a manner that the main beam axis 48 of each of the light-emitting diodes 34 slopes away from the light outlet pane 30.
When seen in the sectional plane of
In a region in which the light reflection surface 44 is visible when viewed perpendicularly through the light outlet pane 30, the light reflection surface 44 has a roughness depth Rz according to DIN EN ISO 4287 in a range between 2.5 μm and 8.0 μm, preferably between 3.0 μm and 6.5 μm. The arithmetical mean roughness value Ra according to the same DIN EN ISO standard is, in the case of those Rz values, in a range between 0.63 μm and approximately 2.4 μm, preferably between 0.8 μm and 2.0 μm. If these values of Rz and Ra are expressed on the basis of the reference classes defined in guideline VDI 3400 (VDI: Verein Deutscher Ingenieure [association of German engineers]), the roughness of the light outlet pane 30 lies in a range between 16 and 28, preferably between 18 and 26 or 27. This ensures diffuse reflection of the light of the light-emitting diodes 34 at the light reflection surface 44 and good homogenisation of the brightness distribution at the surface of the light outlet pane 30 perceived by an observer. In the example of
In the exemplary embodiment shown in
In the further figures, components which are the same or have the same effect are provided with the same reference numerals as before, but with the addition of a lowercase letter. Unless indicated otherwise hereinbelow, reference is made for the explanation of such components to the above observations in relation to
In the lighting module 26a shown in
In the embodiment according to
In the example shown, the clamping elements 62b are in the form of spring tongues which protrude with their free tongue ends from the frame front part 66b. When the frame 36b is fitted into the opening 38b of the delimiting wall 40b, the clamping elements 62b are first pushed behind the delimiting wall 40b, whereby the clamping elements 62b experience a certain deflection. As soon as the clamping elements 62b are engaged sufficiently far behind the delimiting wall 40b, the frame 36b can be pivoted fully into the opening 38b. The clamping elements 64b thereby pass through the opening 38b. As soon as the frame front part 66b is resting on the delimiting wall 40b on all sides, this insertion movement of the lighting module 26b oriented transversely to the wall plane of the delimiting wall 40b is complete. Fitting is continued by a subsequent locking movement, which takes place without further pivoting of the frame 36b in the direction along the rectangle side on which the clamping elements 64b are formed. This locking movement is thus carried out while the frame front part 66b is resting on the delimiting wall 40b on all sides.
The clamping elements 64b form a clamping slot 68b between themselves and the bottom side of the frame front part 66b. The opening 38b is so shaped that, in association with each of the clamping elements 64b, it forms a wall web which, during the described locking movement of the frame 36b, moves into the clamping slot 68b of the associated clamping element 64b. In the example shown, the clamping elements 64b are each formed by a spring leaf or clip which is clamped in the region of its two clip ends and is elastically deflectable in the region of its clip middle portion 70b. The slot width of the clamping slot 68b is defined by the distance of the clip middle portion 70b from the bottom side of the frame front part 66b. During the locking movement, the wall web of the delimiting wall 40b associated with a respective clamping element 64b is clamped in the clamping slot 68b in question. The clip middle portion 70b of each clamping element 64b thereby presses the wall web in question against the frame front part 66b. The clamping elements 64b may therefore also be referred to as pressing elements.
Owing to the resilience of the clamping elements 62b, 64b, the exemplary embodiment according to
Although the preferred embodiments of the present invention have been described herein, the above description is merely illustrative. Further modification of the invention herein disclosed will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the invention as defined by the appended claims.
Number | Date | Country | Kind |
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10 2017 011 926 | Dec 2017 | DE | national |
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