Heatable cooling device glazing

Abstract

The invention relates to a glazing (100) for a cooling device (102), comprising - at least one optical waveguide (1) for guiding radiation (3) in the IR wavelength range, comprising a first surface (I) and a second surface (11), and - at least one radiation source (2) for radiation (3) in the IR wavelength range of A = 1.3 µm to 3.5 µm, - an IR-reflective coating (4) which extends at least partly over the surface of the optical waveguide (1), - an outer pane (11), and - a spacer (7) which is arranged between the optical waveguide (1) and the outer pane (11), wherein the radiation source (2) is arranged relative to the optical waveguide (1) such that the radiation (3) emitted by the radiation source (2) can be coupled into the optical waveguide (1).

Description

[0001] Heatable refrigerator glazing

[0002] The invention relates to a refrigerator glazing and a refrigerator with such glazing.

[0003] Refrigeration appliances such as refrigerators and freezers are often used to preserve perishable foods or medications for longer. The low temperatures in refrigeration appliances slow down chemical reactions and biological processes that, for example, render food inedible and medication unusable. Glass-enclosed refrigeration appliances, particularly glass-enclosed refrigerators and freezers, have become particularly popular in retail. Glass-enclosed refrigeration appliances make the contents of the refrigeration appliance visible without the need to open the appliance. This saves energy, as every opening of the refrigeration appliance results in energy loss, and it also makes it easier to find the desired products in the refrigeration appliance.

[0004] However, a well-known problem with glazed refrigerators is fogging of the glass surfaces exposed to the refrigerator's interior. When these surfaces come into contact with warm air when the refrigerator is opened, the moisture in the ambient air condenses on these surfaces. This results in reduced visibility through the refrigerator's glass.

[0005] To prevent condensation, coatings are often used on the glass surfaces of refrigerators. For example, DE2454657A1 describes a coating based on phosphorus pentoxide that counteracts condensation. EP1499218B1 discloses a coating based on various isocyanates on a refrigerator door, which partially prevents or inhibits fogging or clouding of the refrigerator door. Another particularly energy-intensive solution is the continuous heating of the glass surfaces using heating wires or heating layers.

[0006] However, these known solutions have the problem that they usually do not completely prevent fogging of the window, but often only inhibit condensation. Secondly, these coatings wear out over time; for example, they degrade as a result of the window's exposure to UV radiation or are slowly removed by contact with the window. Continuous heating, on the other hand, requires a lot of energy. Independent of these solutions, DE102017201190A1 concerns a refrigeration appliance, for example a refrigerator, in which the condition of food is checked using an IR-radiation-conducting shelf. For this purpose, IR radiation in a wavelength range from 780 nm to 3000 nm is coupled into a light-conducting area of ​​the shelf. An IR radiation detector simultaneously measures the IR radiation emerging from the shelf at another location.The condition of certain foods can be determined based on the difference between incoming and outgoing radiation.

[0007] WO2023073593A1 relates to a glazing unit comprising at least one optical fiber into which IR radiation in the range of 780 nm to 4000 nm can be coupled to remove fogging or frost. The glazing system is primarily designed for vehicle windows, but can also be used in refrigerators.

[0008] US2017013679A1 discloses a vehicle window assembly in which IR radiation is radiated onto a pane that absorbs IR radiation. The pane heats up due to absorption, allowing water and frost to be removed from the pane. Accordingly, the pane is made of a material that has a high absorption capacity for the radiated radiation. Similarly, WO2017137111A1 discloses a glazing system for a vehicle in which a radiation source is arranged in a recess of a light-conducting pane. The radiation emitted by the radiation source is at least partially coupled into the pane and serves to monitor elements in the pane or to heat the pane.

[0009] The present invention is based on the object of providing a refrigerator glazing that overcomes the above-mentioned disadvantages, is safe for users, and has lower energy consumption. The invention is also based on the object of providing a refrigerator with such glazing.

[0010] The object of the present invention is achieved by a refrigerator glazing according to claim 1 and a refrigerator according to claim 14. Preferred embodiments are evident from the subclaims.

[0011] The refrigerator glazing according to the invention comprises at least one optical waveguide for conducting radiation in the IR wavelength range and at least one radiation source for radiation in the IR wavelength range from λ = 1.3 pm to 3.5 pm, hereinafter also referred to as IR radiation. The radiation source is arranged in relation to the optical waveguide in such a way that the radiation emitted by the radiation source can be coupled into the optical waveguide. The wavelength λ (lambda) is the smallest distance between two points of the same phase of a wave. The refrigerator glazing is designed as multiple glazing and also comprises an outer pane and a spacer which is arranged between the optical waveguide and the outer pane. The refrigerator glazing therefore comprises at least the outer pane and one further pane. The further pane is, for example, an inner pane to which the optical waveguide is applied as a coating.Alternatively, the optical fiber can also be designed as a single pane, thus forming the additional pane. The refrigerator glazing can also comprise more than two panes; preferably, it comprises at least three panes.

[0012] The refrigerator glazing is preferably insulating glazing with at least one inner pane and one outer pane, which are connected to one another via a spacer. The optical fiber is preferably the inner pane, i.e. the pane which is intended to be adjacent to the interior of the refrigerator. Alternatively, the optical fiber can also be a coating on the inner pane. The refrigerator glazing can also have more than two panes and can be triple glazing, for example. Refrigerator glazing refers to glazing for refrigeration appliances such as refrigerators and freezers. The refrigerator glazing is intended to separate the interior of a refrigerator from the outside environment in an opening. It is particularly preferably the glazing of the refrigerator door, which can also refer to a refrigerator flap or sliding door.

[0013] According to the invention, the optical waveguide has a first surface and a second surface. The first surface is intended to face the external environment when installed in a refrigerator. The second surface is intended to face the interior of the refrigerator when installed in a refrigerator. According to the invention, the first surface of a pane which is a component of the refrigerator glazing is intended to face the external environment when installed in a refrigerator. According to the invention, the second surface of a pane which is a component of the refrigerator glazing is intended to face the

[0014] Facing the interior of the refrigerator. The radiation source couples IR radiation in a wavelength range from A = 1.3 pm to 3.5 pm into the optical fiber. Due to the lower refractive index of water compared to glass, the coupled IR radiation can be coupled out advantageously selectively by ice or water on the surface of the optical fiber. The IR radiation is absorbed and water molecules in ice crystals and water droplets are excited by the IR radiation, which causes the ice to melt and the water to evaporate. Energy loss through convection is advantageously largely avoided. The refrigerator glazing is therefore free of fogging or icing and visibility through the glazing can be guaranteed even if the refrigerator is opened frequently.

[0015] By coupled-in IR radiation we mean that the IR radiation propagates within the optical waveguide using the effect of total internal reflection. This takes advantage of the fact that the surfaces of the optical waveguide are either transparent to IR radiation or reflect the IR radiation, depending on the angle of incidence of the radiation and the refractive index of the adjacent medium. Mixtures of reflection and transmissivity are also possible. Whether the IR radiation is reflected by the optical waveguide or transmitted through the optical waveguide depends, as already mentioned, on the angle of incidence θi of the IR radiation on the surface of the optical waveguide, which forms the interface between the optical waveguide and the adjacent medium. Interfaces of the optical waveguide refer to the surfaces of the optical waveguide, since these are where the optical waveguide borders a neighboring medium. An example of a neighboring medium is air or water.The angle at which IR radiation is reflected also depends on the refractive index of the optical fiber m and the refractive index of the adjacent medium n2 (e.g., optical fiber = glass and adjacent medium = air). Whether the IR radiation is deflected at the interface or completely reflected (exit angle 82) can be estimated using Snell's law of refraction (-sin^2) = sin(02) - n2.

[0016] The reason why IR radiation can be coupled out at the wet glass surface while being reflected at the glass surface adjacent to the air is the change in the angle of total reflection 0T of the IR radiation at the interface between water and glass (the contact surface with water). The angle of total reflection indicates the angle at which the incident light is totally reflected: — = sin(6 T). Water has a refractive index of approximately 1.3, glass has a refractive index of approximately 1.5, and air has a refractive index of approximately 1.0. The angle of total internal reflection is therefore larger for the glass-water interface than for the air interface. In other words, there is a range of angles of incidence in which the IR radiation is totally reflected at the glass-air interface, whereas it is at least partially outcoupled at the glass-water interface.

[0017] A major advantage of the invention is that large-area, electrically heatable layers, such as silver coatings or anti-fog coatings, can be dispensed with. This leads to simplified, more cost-effective production of the refrigerator glazing. The selective heating of water using IR radiation also saves energy costs. The permeability of high-frequency radiation, for example, for receiving mobile phone signals, communicating with cloud servers ("Internet of Things"), and the like, is not impaired by the inventive IR radiation heating, thus resulting in further advantages. By coupling the IR radiation into the optical fiber, the IR radiation largely does not reach the external environment and therefore does not pose a health risk to users of the refrigerator.Those residual portions of the IR radiation that are not coupled out at moist areas of the optical fiber according to the invention are instead largely coupled out via the peripheral edge surface of the optical fiber. The technical effect of energy savings is further enhanced by the use of multiple glazing, including an outer pane, as this reduces the amount of external heat generated by the optical fiber, thus saving energy for cooling the refrigerator's interior.

[0018] The optical fiber, particularly when formed as a disc, preferably a glass disc, has a circumferential edge surface. The circumferential edge surface comprises an upper edge and a lower edge, as well as two side edges connecting the upper and lower edges. In the installed position, the upward-facing edge of the optical fiber is referred to as the upper edge, and the downward-facing edge is referred to as the lower edge. The edges running in between are referred to as side edges. If the optical fiber is a coating on a disc, preferably a glass disc, the coated disc also has a circumferential edge surface with an upper edge, lower edge, and side edges.

[0019] In a particularly preferred embodiment of the invention, the radiation source is arranged such that its position relative to the optical fiber does not change even when the refrigerator glazing is moved. This means that if, for example, the refrigerator glazing is part of a refrigerator door or refrigerator flap that can be opened and closed, the radiation source is positioned the same relative to the optical fiber even during opening or closing and at the respective start and end points of the refrigerator door. In this case, the radiation source could, for example, be attached to a top edge, bottom edge, and / or side edge of the optical fiber or the pane coated with it. This also means that the relative position of the optical fiber to the radiation source is the same everywhere, regardless of location.This ensures efficient heating in any position of the refrigerator (e.g., an open or closed refrigerator). Particularly preferably, the radiation source is firmly connected to the optical fiber, preferably by adhesive bonding. If the optical fiber is a coating on a pane, preferably a glass pane, the radiation source can also be firmly connected to this pane, preferably by adhesive bonding. The adhesive used for bonding is preferably an optically clear adhesive based on polyacrylic compounds.

[0020] In a further preferred embodiment, the radiation source is suitable for emitting IR radiation in the IR wavelength range from A = 2.5 pm to A = 3.3 pm, preferably from A = 2.6 pm to A = 3.1 pm, particularly preferably from A = 2.6 pm to A = 2.9 pm. It is precisely in this preferred wavelength range that the absorption and excitation of the water molecules and thus the resulting heating and evaporation are particularly high. Advantageously, it has been shown that in the case of glass, the transmission in the wavelength range from A = 2.9 pm to A = 3.1 pm is particularly high at over 70%, in particular at approx. A = 3.0 pm at approx. 85%, so that the energy can be used efficiently for defrosting and evaporating water.

[0021] In an alternative embodiment, the radiation source is suitable for emitting IR radiation in the IR wavelength range from A = 1.45 pm to A = 1.95 pm. In this range, the radiation is particularly energy-intensive and thus very suitable for evaporating water. This wavelength range is particularly preferred if the radiation source comprises or consists of an LED, since LEDs with radiation in higher wavelength ranges above 2 pm are difficult to manufacture and thus incur high costs.

[0022] The at least one radiation source used emits radiation in the IR radiation range from 1300 nm to 3500 nm, for example radiation in the range from 1600 nm to 3100 nm, but particularly preferably in the range from 2900 nm to 3100 nm. It is not necessary for the emission band of the radiation source to completely cover the aforementioned ranges. However, the emission band should lie (at least partially) within these ranges. The radiation source is expediently connected to a power supply device during use. The radiation source preferably comprises at least one LED, OLED and / or a laser diode, preferably at least one LED. In particular, the radiation source comprises at least one LED, which can also be referred to analogously as an "IR radiation-emitting diode". Furthermore, the radiation source can comprise laser diodes or lasers, which have the advantage of being particularly powerful and efficient.In addition to the aforementioned elements for generating IR radiation, the radiation source may also comprise other elements, such as a housing in which the elements for generating IR radiation are mounted. Alternatively, the radiation source may be an LED, OLED, and / or a laser diode.

[0023] In a particularly preferred embodiment of the invention, the radiation source comprises or consists of an Er:YAG diode. The Er:YAG diode has a wavelength of approximately 2960 nm. This wavelength corresponds to the wavelength range in which water molecules exhibit the highest absorption coefficient. Other examples are InAs / GaSb and Er3+-doped sesquioxide diodes.

[0024] The refrigerator glazing can also comprise more than one radiation source, for example 2, 3 or 4 radiation sources. The at least one radiation source can be strip-shaped or spot-shaped, for example. Other geometric shapes are also possible. Several individual radiation sources can also be arranged next to one another, spaced apart, or in a strip-shaped manner (close to one another). If several spot-shaped LEDs are arranged next to one another, in other words, a multi-part, strip-shaped radiation source can be formed. This makes it possible to flexibly adapt the number and intensity of the radiation sources to the requirements for heating the respective refrigerator glazing, for example with regard to the spatial-geometric conditions and the energy required for efficient heating.

[0025] The optical waveguide can, for example, be formed as a pane. Alternatively, the optical waveguide can be applied as a coating to one of the surfaces of the pane (not the outer pane), in particular the surface which, when installed, faces the interior of the refrigerator. Particularly preferably, the optical waveguide is applied as a coating to the second surface of the pane as well as to the first surface of the pane. The pane is therefore coated with the optical waveguide on each of its main surfaces. In this embodiment, the refrigerator glazing preferably comprises a further radiation source, such that the first radiation source couples IR radiation into the optical waveguide on the first surface of the pane and the further radiation source couples IR radiation into the optical waveguide on the second surface of the pane.

[0026] In a preferred embodiment, the optical waveguide is designed as a disc, preferably as a glass disc, particularly preferably made of soda-lime glass. In principle, however, the disc can also be made of other types of glass (e.g. borosilicate glass, quartz glass, aluminosilicate glass). Alternatively, the disc can also be made of plastic, i.e. transparent polymers, e.g. polycarbonate. The thickness of the disc can vary widely. Preference is given to discs with a thickness in the range of 0.5 mm to 10 mm, preferably from 1 mm to 5 mm. The optical waveguide is preferably a glass disc and particularly preferably has an iron oxide content of a maximum of 1%. This low iron oxide content of the glass disc makes the glass disc particularly suitable as an optical waveguide for IR radiation.

[0027] In an alternative embodiment, the optical waveguide is applied as a coating to a pane (not the outer pane), and the pane is preferably designed as a glass pane, particularly preferably as a glass pane made of soda-lime glass. Here, too, the pane can in principle also be made of other types of glass (e.g., borosilicate glass, quartz glass, aluminosilicate glass). Alternatively, the pane can also be made of plastic, i.e., transparent polymers, such as polycarbonate. The thickness of the pane can vary widely. Preference is given to panes with a thickness in the range of 0.5 mm to 10 mm, more preferably 1 mm to 5 mm.

[0028] If a coating is based on a material, it consists predominantly of this material, in particular essentially of this material, along with any impurities or dopants.

[0029] "Transparent" in the sense of the invention means a visible light transmission (according to ISO 9050:2003) of at least 70%, preferably at least 80%, and particularly preferably at least 90%. "Semi-transparent" (according to ISO 9050:2003) in the sense of the invention means a light transmission of at most 70%, preferably at most 50%, and particularly preferably at most 30%. "Opaque" in the sense of the invention means a light transmission (according to ISO 9050:2003) of less than 30%, preferably less than 20%, particularly preferably less than 5%, and in particular less than 0.1%. According to the invention, the refrigerator glazing is a multiple glazing unit, preferably an insulating glazing unit, with at least one inner pane and one outer pane, which are connected to one another via a spacer. According to the invention, the spacer is arranged between the optical fiber and the outer pane.The optical waveguide is particularly preferably the inner pane of the glazing or, alternatively, is applied as a coating to the second surface of the inner pane. Particularly preferably, the optical waveguide is formed as a single pane, and the spacer connects the outer pane and the optical waveguide to one another.

[0030] The refrigerator glazing is preferably insulating glazing with a maximum of one inner pane and one outer pane, such that the first surface of the outer pane has a surface exposed to the external environment. However, the refrigerator glazing can also be insulating glazing with more than two panes. For example, the refrigerator glazing can be triple glazing comprising an inner pane, a middle pane, and an outer pane. In this case, the optical fiber is particularly preferably the inner pane of the glazing or, alternatively, applied as a coating to the second surface of the inner pane. The inner pane is preferably connected to the middle pane via a spacer, and the middle pane is connected to the outer pane via a further spacer.

[0031] The spacer is typically frame-like and arranged in the edge area between the two panes to keep them (usually plane-parallel) at a defined distance from each other. The spacer is typically made of a light metal (particularly aluminum) or of polymeric materials (e.g., polypropylene or styrene-acrylonitrile). It is preferably in contact with the two panes via a sealing compound, particularly a butyl sealing compound. An external sealing compound, particularly organic sealing compounds made of or based on polysulfides, silicones, RTV (room-temperature-curing) silicone rubber, HTV (high-temperature-curing)

[0032] Silicone rubber, peroxide-cured silicone rubber and / or addition-cured silicone rubber, polyurethanes, butyl rubber, and / or polyacrylates. The inner space between the panes, which is defined and enclosed by the glass panes and the spacer, is preferably evacuated or filled with an inert gas, such as argon or krypton. The space between the panes reduces thermal conductivity, allowing more energy-efficient temperature regulation in the refrigerator interior. The spacer typically has a cavity filled with a desiccant to protect the space between the panes from moisture penetration.

[0033] The inner pane, the outer pane, and any central pane, as well as any additional panes, are preferably formed as glass panes, particularly preferably as glass panes made of soda-lime glass. Here, too, the panes can, in principle, also be made of other types of glass (e.g., borosilicate glass, quartz glass, aluminosilicate glass). Alternatively, the panes can also be made of plastic, i.e., transparent polymers, such as polycarbonate. The thickness of the panes can vary widely. Preference is given to panes with a thickness in the range of 0.5 mm to 10 mm, more preferably 1 mm to 5 mm.

[0034] The optical waveguide is preferably a ceramic coating that is transparent. The optical waveguide preferably has a layer thickness of at least 650 nm, particularly preferably from 700 nm to 5 pm, most preferably from 750 nm to 4 pm, in particular from 800 nm to 3 pm. The optical waveguide can contain or consist of titanium oxide, aluminum oxide, silicon nitride, in particular SiA1N4, silicon zirconium nitride, silicon oxynitride, and / or silicon dioxide, in particular SiO2. The optical waveguide particularly preferably contains silicon nitride and / or titanium dioxide. In particular, the optical waveguide is formed based on a silicon nitride layer and / or a titanium dioxide layer. It can also consist of a silicon nitride layer and / or a titanium dioxide layer. These materials are particularly suitable as optical waveguides for IR radiation and additionally have a high transmittance for visible light.

[0035] In a preferred embodiment of the invention, the refrigerator glazing additionally comprises an IR-reflecting coating. When the glazing is installed in a refrigerator, the IR-reflecting coating is intended to prevent IR radiation from escaping into the external environment. The IR-reflecting coating is preferably applied to the first or second surface of the outer pane or to the first surface of the inner pane. In the case of triple glazing, the IR-reflecting coating can also be applied to the first or second surface of the middle pane. The IR-reflecting coating is particularly preferably applied to the first surface of the optical fiber, in particular when the optical fiber is designed as a pane. The IR-reflecting coating preferably extends over the entire area of ​​the refrigerator glazing intended for transparency.The IR-reflecting coating preferably extends over at least 80% of the surface of the optical waveguide, particularly preferably over at least 90%. The IR-reflecting coating is most preferably arranged such that, when viewed through the refrigerator glazing, it is congruent with the optical waveguide, i.e., extends over the entire surface of the optical waveguide.

[0036] The IR-reflecting coating can comprise metallic layers, for example at least one metallic layer, or be metal-free. Particularly preferably, the IR-reflecting coating comprises at least one silver layer and preferably a plurality of silver layers. Such silver layers have particularly advantageous reflection properties while simultaneously providing high transmission in the visible spectral range. The thickness of a silver layer is preferably from 1 nm to 50 nm, particularly preferably from 5 nm to 25 nm. In this range for the thickness of the silver layer, advantageously high transmission in the visible spectral range and particularly advantageous electrical conductivity are achieved.

[0037] The IR-reflecting coating most preferably comprises at least two silver layers, in particular at least three silver layers. Preferably, at least one dielectric layer is arranged between each two adjacent silver layers of the coating. A dielectric layer contains at least one individual layer made of a dielectric material, for example containing a nitride such as silicon nitride or an oxide such as aluminum oxide. However, dielectric layers can also comprise several individual layers, for example individual layers of a dielectric material, smoothing layers, adaptation layers, blocking layers, and / or anti-reflection layers. The thickness of a dielectric layer is, for example, from 10 nm to 200 nm. This achieves the technical advantage, for example, that infrared light can be effectively blocked.The blocking of infrared light is particularly well achieved when the infrared protective layer comprises at least two silver layers, particularly preferably three silver layers and in particular exactly three silver layers.

[0038] In a particularly preferred embodiment of the invention, the IR-reflecting coating is applied to the first surface of the optical waveguide, or if the optical waveguide itself is a coating on a disc, arranged between the optical waveguide and the coated disc. The IR-reflecting coating has a lower refractive index than the optical waveguide. The IR-reflecting coating here has a refractive index preferably of less than 1.5, preferably less than 1.4. This effectively blocks the IR radiation and at the same time increases the effect of total internal reflection, whereby the IR radiation remains coupled within the optical waveguide for longer and is more likely to strike a spot on the second surface of the optical waveguide containing water.

[0039] In a further preferred embodiment, the at least one radiation source can be functionally connected to at least one sensor, in particular a temperature and / or humidity detector. This can advantageously be used for automated defrosting or the removal of condensed moisture. In addition, icing of the refrigerator glazing or the formation of condensate and the associated obstruction of visibility can also be prevented. The sensor is preferably attached to the optical fiber or, if the optical fiber is a coating on a pane, to the pane.

[0040] In a further preferred embodiment of the invention, the at least one radiation source is arranged on at least a section of a circumferential edge surface of the optical waveguide or the edge surface of the pane to which the optical waveguide is applied. The radiation source is, for example, assigned to at least one lateral edge surface or attached to two opposite lateral edge surfaces and / or to the upper edge and / or the lower edge, for example, glued or arranged in a holder fastened to the pane. The IR radiation is then coupled into the optical waveguide via one, two, three or four, or if available, more (for example, all) edge surfaces. It can be advantageous to irradiate the optical waveguide from one or more sides with multiple radiation sources in order to increase the heating effect accordingly. In particular, the radiation source is arranged on the lower edge.This is a good option because it's usually the most visually unobtrusive arrangement. The bottom edge of the refrigerator's glass is usually concealed by components of the refrigerator and is not at user eye level.

[0041] In a further embodiment of the invention, the at least one radiation source is arranged in a recess of the optical waveguide. If the optical waveguide is a coating on a disc, the disc preferably also has a recess in which the radiation source is arranged. The radiation source is arranged in the recess such that the radiation source can couple IR radiation into the optical waveguide, which then serves either to remove condensed moisture or for defrosting. The optical waveguide thus has a recess. This recess is preferably a hole, i.e., a feedthrough, which extends between the first and second surfaces of the optical waveguide.However, if the optical waveguide is a disc, the recess can alternatively also be a depression in the manner of a blind bore (bag-like depression), which extends from the second surface or the first surface into the disc, but without reaching the opposite main surface, which would result in a feedthrough. The recess can be created in the optical waveguide, for example, by mechanical drilling or by laser processing. The recess is preferably round, but can basically have any desired shape, for example even a polygonal shape. This refers to the base area of ​​the recess in the plane of the at least one surface of the optical waveguide, via which the recess is introduced into the optical waveguide. The recess has the overall shape of a cylinder, preferably a vertical cylinder.The cylinder is preferably a circular cylinder (circular base), but can also have any other base areas, for example an elliptical base (elliptical cylinder) or a polygonal base (prism).

[0042] The recess, whether in the form of a feedthrough or a depression, is defined by a circumferential edge surface extending between the main surfaces of the optical fiber. If the optical fiber is applied as a coating to a disk, and both the optical fiber and the disk have a recess, the coated disk also has a circumferential edge surface. In the case of a feedthrough, this is the only boundary surface of the recess. In the case of a pocket-like depression, there is a further boundary surface facing the main surface of the optical fiber to which the depression does not extend, and which, as it were, forms the bottom of the pocket hole.If the optical fiber is formed as a coating on a disc, a recess in the form of a pocket-like depression means that the optical fiber has a feedthrough and the disc to which it is applied has a pocket-like depression, which was created, for example, by means of a blind bore. The feedthrough of the optical fiber and the pocket-like depression of the disc are arranged essentially congruent with each other.

[0043] The radiation source is arranged on the edge surface of the recess of the optical waveguide / coated pane, preferably attached, in particular glued, or arranged in a mount attached to the recess. The IR radiation is then coupled into the optical waveguide via the inner edge surface and, due to the lower refractive index of water, selectively coupled out of the interior of the optical waveguide in the presence of ice or in areas with condensed moisture.

[0044] In another embodiment, the optical waveguide is formed as a disk, and the at least one radiation source is preferably arranged in an edge region of the optical waveguide on the second surface. In particular, a further radiation source is preferably arranged in an edge region of the optical waveguide on the first surface. In the edge region, the radiation sources are less visually noticeable and can be easily concealed by components of the cooling device. The use of two radiation sources can be useful to improve the incident radiation intensity.

[0045] In one embodiment, the radiation source is applied to the second surface of the optical waveguide, and an IR mirror layer, i.e. a reflective coating for the infrared range, is applied to the first surface of the optical waveguide, which is arranged so as to cover the at least one radiation source when viewed through the refrigerator glazing. The optical waveguide is thus irradiated with IR radiation via the second surface. The at least one radiation source is attached to the second surface of the optical waveguide, for example, adhered with an optically clear adhesive (OCA). As a result, the IR radiation is coupled into the optical waveguide via reflection from the IR mirror layer. This reduces the complexity of the refrigerator glazing, since the radiation source does not have to be arranged on the edge surfaces of the optical waveguide.Alternatively, the IR mirror layer can also be applied to the second surface of the optical waveguide. In this case, the radiation source is arranged or applied to the first surface of the optical waveguide. When viewed through the refrigerator glazing, the IR mirror layer and the radiation source are preferably arranged overlapping one another. The IR mirror layer is preferably designed as an IR radiation-reflecting prism film.

[0046] An optically clear adhesive is preferably a material that contains or is made from polyacrylate compounds (e.g., polyacrylate or polymethylacrylate) or silicone. "Clear" in the context of the invention means that the adhesive is transparent.

[0047] When using an IR mirror layer for coupling, the IR radiation from the radiation source is (at least partially) reflected back toward the optical fiber by the IR mirror layer, where the IR radiation is coupled into the optical fiber via coupling using the principle of total internal reflection. This helps distribute the IR radiation within the optical fiber and direct it to the areas to be heated, such as icy or damp areas of the refrigerator's glazing.

[0048] IR mirror layers are known per se and can be formed, for example, as a silver-containing coating or as a layer of an electrically conductive oxide (transparent conductive oxide, TCO), such as indium tin oxide (ITO). Alternatively, the IR mirror layer can also be arranged in the form of a coated thermoplastic film, for example made of polyethylene terephthalate (PET), on the optical fiber or between the optical fiber (which is formed as a coating) and a pane. In this embodiment, the radiation source(s) is / are preferably arranged in a region of the optical fiber that cannot be seen from the external environment in the installed position (for example, concealed by seals or other components of the cooling device).The IR mirror layer is preferably an IR-reflecting prism film, which is preferably additionally coated with an IR-reflecting coating based on an electrically conductive oxide. In particular, the IR mirror layer is a microprism film, which can be additionally coated with an IR-reflecting coating based on an electrically conductive oxide. If the prism film or microprism film is coated with an IR-reflecting coating, it can also be transparent to IR radiation, so that the IR radiation is only reflected by the IR-reflecting coating. The inclined surfaces of the prism film result in the IR rays being reflected at a particularly advantageous angle by the IR mirror layer, so that they strike the optical fiber at an angle of incidence at which a particularly high proportion of the IR radiation can be coupled in.

[0049] Mixtures and combinations of the above-described embodiments are also possible. For example, the optical fiber can be irradiated and heated with a radiation source on the lower edge and additionally with a further radiation source on the second surface of the optical fiber. Likewise, a radiation source can be arranged in a recess in the optical fiber / coated pane and an additional radiation source can be attached to an edge. These are only exemplary embodiments and are not to be understood as exhaustive. In a further embodiment of the invention, the refrigerator glazing comprises at least one further radiation source, preferably at least two further radiation sources, which are suitably arranged to be able to couple IR radiation into the optical fiber. The radiation sources can preferably be switched and operated independently of one another.The assigned radiation sources can be controlled independently of each other so that the heating strength or intensity can be selectively adjusted.

[0050] In a preferred embodiment, the radiation source is arranged in an opaque region, preferably an edge region, of the refrigerator glazing, which completely covers the radiation source when viewed through the refrigerator glazing. The radiation sources can thus be optically concealed from the outside. To prevent the opaque region from blocking the coupling of the IR radiation into the optical fiber, a small recess in the opaque region—i.e., a small non-opaque region—can be provided in the area of ​​the IR beam path.

[0051] For the purposes of the invention, the “complete occlusion / coverage of an element A with an element B” means that the orthonormal projection of element A to the plane of element B is arranged completely within element B.

[0052] Refractive indices in the context of the present invention are generally given relative to a wavelength of 1500 nm. Methods for determining refractive indices are known to those skilled in the art. The refractive indices specified in the context of the invention can be determined, for example, by ellipsometry, using commercially available ellipsometers. Unless otherwise stated, the specification of layer thicknesses or thicknesses refers to the geometric thickness of a layer.

[0053] If the optical waveguide is designed as a disc, it can also be provided with an emissivity-reducing coating on its first surface or its second surface. If the optical waveguide itself is designed as a coating and applied to a disc, the disc coated with the optical waveguide can have an emissivity-reducing coating. Such a disc preferably has the emissivity-reducing coating on its first surface. The emissivity-reducing coating can also be applied to the inner disc, the outer disc, or any middle disc that may be present, wherein, if applied to the middle or outer disc, it is preferably applied to its second surface. If the emissivity-reducing coating is applied to the inner disc, it is preferably applied to its first surface.

[0054] The emissivity-reducing coating is a coating that reflects heat radiation. This type of coating is often referred to as a low-E coating or low-emissivity coating. Its function is to prevent heat radiation from entering the interior (thermal radiation from the pane itself) and also to prevent heat radiation from leaving the interior. For the purposes of this invention, emissivity is understood to be the normal emissivity at 283 K according to the EN 12898 standard.

[0055] The emissivity-reducing coating is preferably a sequence of thin layers (layer structure, layer stack). One layer is an electrically conductive layer, whereas the optical properties (transmission and reflectivity) of the coating are largely determined by the remaining layers and can thus be specifically adjusted through their design. So-called anti-reflective coatings, which have a low refractive index of preferably no more than 1.8 and particularly preferably no more than 1.6, have a particular influence in this context. These anti-reflective coatings can increase the transmission through the pane and reduce the reflectivity, particularly as a result of interference effects. The effect depends crucially on the refractive index and layer thickness.

[0056] The refrigerator glazing can be flat or curved in one or more directions of the room. Preferably, however, the refrigerator glazing is not curved, i.e., essentially flat. The refrigerator glazing preferably also has an essentially rectangular shape in plan view, with the corners possibly being rounded. "Essentially rectangular" therefore excludes trapezoidal glazing.

[0057] The invention also extends to a refrigerator comprising the refrigerator glazing according to the invention as described above.

[0058] The cooling device can be, for example, a refrigerator, a freezer, a freezer chest, or a freezer. Preferably, the cooling device is a refrigerator or a freezer chest.

[0059] The refrigerator glazing is preferably arranged in the refrigerator in such a way that it separates the refrigerator's interior from the external environment. The refrigerator glazing is intended to allow a view into the refrigerator without having to open the refrigerator. It is therefore preferably a component of the refrigerator that is visible from the external environment when the refrigerator is closed.

[0060] In a particularly preferred embodiment of the invention, the refrigerator further comprises at least one refrigerator door. For the purposes of the invention, a refrigerator door refers to a movable component provided for closing and opening the refrigerator. The refrigerator door can thus be a hinged door, a hinged door, a sliding door, a pivoting sliding door, etc. Various types of refrigerator doors are known per se to those skilled in the art, so a detailed description is unnecessary here.

[0061] Particularly preferably, the refrigerator door comprises the refrigerator glazing according to the invention. The refrigerator glazing is thus a component of the refrigerator door. Particularly preferably, the refrigerator glazing is arranged as a component of the refrigerator door in such a way that the second surface of the optical fiber is the surface exposed to the refrigerator interior. This is advantageous because the inside of the refrigerator door comes into contact with the outside environment when the door is opened, and water subsequently forms on the cooled inside through condensation, which can then be removed according to the invention.

[0062] In a further preferred embodiment of the invention, the cooling device further comprises a moisture detector for detecting water on the first surface and / or the second surface of the optical fiber, and a control unit. The moisture detector is preferably configured such that it sends a signal, referred to here simply as signal A, to the control unit when water is present on the first surface and / or the second surface of the optical fiber. In this case, the control unit is configured such that, at least upon receipt of signal A, it electronically controls the radiation source so that the radiation source emits IR radiation that is coupled into the optical fiber. This offers the advantage that the radiation source is only in operation when water is deposited on the optical fiber, whereby the energy consumption of the radiation source can be significantly reduced.The humidity detector is preferably mounted on the refrigerator glazing so that it can effectively detect water condensed on the first surface and / or the second surface.

[0063] In another particularly preferred embodiment of the invention, the refrigeration device comprises at least one refrigeration device door as described above, a motion sensor, and a control unit. The motion sensor is configured to send a signal, referred to here simply as signal B, to the control unit when the refrigeration device door is open. The control unit is configured to electronically control the radiation source, at least upon receipt of signal B, so that the radiation source emits IR radiation, which is coupled into the optical fiber. This achieves the advantage that the radiation source always emits IR radiation when the door is open and thus generally comes into contact with the ambient humidity. Motion sensors are also significantly cheaper than humidity detectors and less prone to errors.The motion sensor is preferably attached at least to the refrigerator door, for example to the refrigerator glazing. Particularly preferably, one part of the motion sensor is attached to the stop provided for the refrigerator door and another part is attached to the refrigerator door itself. The two parts of the motion sensor are in contact with each other when the refrigerator door is closed and are contact-free when the refrigerator door is open. In the context of the invention, “being in contact with each other” means that, for example, an electronic connection is established between the two parts or the two parts of the motion sensor are directly touching each other. “Being contact-free” in this sense means that the parts are not in contact with each other.

[0064] Particularly preferably, the cooling device has both a humidity detector and a motion sensor, wherein the signal A and the signal B, which is emitted once by the humidity detector and once by the motion sensor, can also be identical.

[0065] The control unit and the moisture detector and / or the motion sensor can be connected via connecting elements such as cables or can be communicatively connected wirelessly. The control unit and the at least one radiation source can also be connected via connecting elements such as cables or can be communicatively connected wirelessly.

[0066] For the purposes of the invention, "closed state" means that the refrigerator door essentially completely separates the refrigerator's interior from the outside environment. "Open state" means that the refrigerator door does not completely close the refrigerator's opening, meaning that the refrigerator's interior is not completely separated from the outside environment.

[0067] The refrigerator glazing can be manufactured, as described above in various embodiments, by a method which comprises at least:

[0068] (A) the radiation source is arranged relative to the optical fiber, (B) so that the IR radiation is coupled into the optical fiber.

[0069] In other words:

[0070] Arranging the radiation source relative to the optical fiber so that the IR radiation emitted by the radiation source can be coupled into the optical fiber.

[0071] Furthermore, the refrigerator glazing can be used in cooling appliances such as refrigerators, freezers, freezer cabinets and / or freezer chests.

[0072] The various embodiments of the invention can be implemented individually or in any combination. In particular, the features mentioned above and those to be explained below can be used not only in the specified combinations, but also in other combinations or on their own, unless they are explicitly described and described as alternatives to one another, without departing from the scope of the present invention.

[0073] The invention is explained in more detail below using exemplary embodiments, with reference to the accompanying figures. They show, in simplified form and not to scale:

[0074] Fig. 1a An embodiment of the cooling device according to the invention in a side view,

[0075] Fig. 1b Top view of an embodiment of the refrigerator glazing according to the invention of the refrigerator from Figure 1a,

[0076] Fig. 1c is a cross-sectional view of the refrigerator glazing from Fig. 1b and a humidity detector of the refrigerator from Fig. 1a,

[0077] Fig. 2-5 further designs of the refrigerator glazing in cross-sectional view,

[0078] Fig. 6 an absorption spectrum of water (liquid state).

[0079] Figures 1a, 1b, and 1c each show different aspects of an embodiment of the refrigerator 102 according to the invention and of an embodiment of the refrigerator glazing 100 according to the invention. Figure 1a shows the refrigerator 102 in a side view looking toward the refrigerator door 101. Figure 1b shows the refrigerator glazing 100 in a plan view, wherein the glazing 100 has an area moistened with water 10. Figure 1c shows the refrigerator glazing 100 from Figure 1b in cross section and also the moisture detector 13 of the refrigerator door 101 in cross section. The moisture detector 13 is electrically connected to a control unit 14 by means of a connecting element, for example a cable. The cross section of Figure 1c is indicated by a dashed line XX' in Figure 1b.

[0080] The refrigerator glazing 100 is a component of the refrigerator door 101 and allows a view from the external environment 9 into the refrigerator interior 8. The refrigerator door 101 comprises a frame, in the center of which the refrigerator glazing 100 is enclosed. A humidity detector 13 is arranged centrally on the upper region of the frame of the refrigerator door 101, for example, glued or screwed on. The upper region of the frame is directly adjacent to the upper edge of the glazing in the installed position. In the present embodiment, the refrigerator glazing 100 is flat, although it is also possible for it to be curved. However, the refrigerator glazing 100 is preferably flat.

[0081] The refrigerator glazing 100 comprises an optical fiber 1 and a radiation source 2. The optical fiber 1 is designed as a glass pane. The glass pane is made, for example, of soda-lime glass. The optical fiber 1 has a thickness of 3.5 mm, for example. The refrigerator glazing 100 also comprises an outer pane and a spacer, wherein the optical fiber 1 and the outer pane are connected to one another via the spacer. The refrigerator glazing 100 according to the invention is therefore a multiple glazing with two panes. The outer pane and the spacer are not shown in Fig. 1c for the sake of simplicity. In the installed position, the upward-facing edge is referred to as the upper edge O. The upper region of the frame of the refrigerator door 101 is directly adjacent to the upper edge O of the refrigerator glazing 100 in the installed position. The downward-facing edge of the optical fiber 1 in the installed position is referred to as the lower edge U.The edges extending therebetween are referred to as side edges S1, S2. The optical waveguide 1 also has a first surface I, which faces the external environment 9, and a second surface II, which faces the interior of the refrigerator 8. A water spot 10 is arranged on the second surface II, for example, in the form of water droplets condensed on the second surface II.

[0082] An IR radiation source 2, which comprises, for example, at least one LED with a wavelength in a wavelength range of A = 1.3 pm to 3.5 pm, is arranged on the lower edge U of the optical waveguide 1. The radiation source 2 can, for example, comprise an Er:YAG diode having a wavelength of approximately 2960 nm. This wavelength corresponds to the frequency and wavelength range in which water molecules have the highest absorption coefficient for the IR radiation 3 (see Figure 6). At the same time, the transmission of glass in this IR radiation range <3.5 pm is particularly high with a transmittance of approximately 85% and only a small part is absorbed. The at least one LED can, for example, be adhesively bonded or arranged in a holder fastened to the optical waveguide 1. In this embodiment, the radiation source 2 is designed and / or arranged in a strip shape.The arrows indicate, by way of example and schematically, the radiation direction of the IR radiation 3. The IR radiation 3 is coupled into the optical fiber 1 via the edge surface at the lower edge U. Furthermore, the radiation source 2 is functionally connected to a control unit 14, for example, via a cable.

[0083] Glass can conduct IR radiation 3 if it is coupled into the pane. In areas where moisture 10 has formed and developed on the optical waveguide 1, i.e. where the optical waveguide 1 is covered, for example, with water droplets 10 or ice crystals, the IR radiation 3 is selectively coupled out because water has a lower refractive index, i.e. is a less optically dense medium than the glass of the optical waveguide 1. The IR radiation 3 is absorbed by the water molecules, which are heated by the excitation from the radiation 3 and thereby evaporate. A particular advantage of the invention is that in particular IR radiation 3 is used which is located in the frequency range in which water molecules have the highest absorption coefficients, and as a result a very selective heating effect can be achieved. This contributes to achieving the heating effect in a particularly energy-saving manner.

[0084] Energy efficiency is an enormously important criterion for future product developments. Advantageously, the heating effect according to the invention does not depend on the heating of the refrigerator glazing 100 itself, but is achieved selectively by the excitation of the water molecules by the IR radiation 3. When heating a refrigerator glazing in a conventional manner, for example, using heating layers, heating must be particularly energy-intensive to counteract the cooling of the refrigerator 102. Therefore, the heating effect of the glazing according to the invention occurs much more quickly than with conventional heating devices, and, in addition, there is no heat loss due to convection and the large surface area of ​​the glazing 100.By firmly attaching the radiation source 2 to the lower edge U of the optical fiber 1, preferably by means of adhesive bonding, the refrigerator glazing 100 can also be movable, for example, it can be opened and closed without the IR radiation 3 being able to be coupled into the optical fiber 1. The use of a moisture detector 13 can increase energy efficiency even further. The moisture detector 13 is connected to the radiation source 2 via a control unit 14. The moisture detector 13 is suitably configured and arranged to detect water 10 on the second surface II of the optical fiber 1. If the moisture detector 13 detects water 10 on the second surface II, it sends a signal to the control unit 14. The control unit 14 is electronically connected to the radiation source 2 and gives the radiation source 2 the command orthe signal to emit IR radiation 3 when the control unit 14 receives a signal from the moisture detector 13. It is understood that the control unit 14 accordingly does not instruct the radiation source 2 to emit IR radiation 3 if the moisture detector 13 does not detect water 10 and therefore does not send a signal to the control unit 14. The cooling device 102 can additionally or alternatively also be connected to a motion sensor, which, like the moisture detector 13, is connected to the control unit 14 (not shown here). The motion sensor can, for example, send a signal to the control unit 14 when the cooling device door 101 is open and not send a signal to the control unit 14 when the cooling device door 101 is closed. Parallel to the variant with the moisture detector 13, the control unit 14 instructs the radiation source 2 to emit IR radiation 3 upon receiving a signal from the motion sensor.

[0085] The variants of the refrigerator glazing 100 shown in Figures 2 to 5 essentially correspond to the variant in Figures 1a, 1b and 1c, so that only the differences will be discussed here and otherwise reference is made to the description of Figures 1a, 1b and 1c. The refrigerator glazings 100 in Figures 2 to 4 also have an outer pane and a spacer arranged between the optical fiber 1 and the outer pane, so that the glazings 100 are multiple glazings (outer pane and spacer are not shown in Figures 2 to 4). In the embodiment according to Figure 5, the outer pane 11 and the spacer 7 are shown in Figure 5. No moisture detectors 13, motion sensors and control units 14 are shown in Figures 2 to 5.However, these can optionally be part of the refrigerator glazing 100 or part of a refrigerator 102 which comprises one of the variants of the refrigerator glazing 100 shown in Figures 2 to 5.

[0086] In Figure 2, in addition to the radiation source 2 at the lower edge U of the optical waveguide 1, a further radiation source 2 is arranged at the upper edge O of the optical waveguide 1, for example glued to the optical waveguide 1. The further radiation source 2 couples IR radiation 3 into the optical waveguide 1 via the upper edge O. In this way, the IR radiation 3 is distributed more evenly over the entire surface of the optical waveguide 1 and is coupled out to water droplets 10 with higher intensity. For example, an IR-reflecting coating 4 is applied over the entire surface of the first surface I of the optical waveguide 1. The IR-reflecting coating 4 comprises, for example, one or more silver layers. The coating 4 largely prevents IR radiation 3 from being coupled out at the first surface I of the optical waveguide 1 and thus reaching the external environment 9.

[0087] In Figure 3, the optical waveguide 1 is not formed as a glass pane, but as a layer based on silicon nitride. The optical waveguide 1 is applied as a coating on a (second) surface ii of a pane 6 facing the refrigerator interior 8. The silicon nitride coating is transparent and suitable for conducting IR radiation 3 by utilizing total internal reflection. The pane 6 is, for example, a glass pane made of soda-lime glass with a thickness of 3.5 mm. The optical waveguide 1 has, for example, a layer thickness of 1 pm. The radiation source 2 is arranged on the (first) surface i of the glass pane 6 facing the external environment 9. The radiation source 2 is arranged in an edge region of the pane 6 adjacent to the lower edge U of the pane 6. The outer pane is connected to the first surface i of the glass pane 6 via the spacer (not shown here).The first surface i of the disc 6 is therefore not exposed to the external environment.

[0088] An IR mirror layer 5 is applied to the second surface II of the optical waveguide 1, i.e. the surface II facing away from the pane 6. The IR mirror layer 5 is, for example, a microprismatic film that is bonded to the optical waveguide 1 by means of an optically clear adhesive. During operation, the radiation source 2 emits IR radiation 3 perpendicular to the pane 6. The IR radiation 3 enters the pane 6 via the first surface i and transmits through it until it exits again via the second surface ii of the pane 6 and enters the optical waveguide 1 via the first surface I. The IR radiation 3 transmits through the optical waveguide 1 and exits at the second surface II of the optical waveguide 1. The IR radiation 3 then strikes the IR mirror layer 5 and is reflected back to the optical waveguide 1.The IR radiation 3 strikes the optical waveguide 1 at such an angle of incidence that it can be at least partially coupled into the optical waveguide 1. Due to the inclined surfaces of the microprismatic film, the IR radiation 3 is reflected at a suitable angle onto the optical waveguide 1. In Figure 4, the optical waveguide 1 is applied as a coating based on silicon nitride to the second surface ii of a disk 6. The disk 6 has a recess 12 in the form of a hole. The hole is, for example, cylindrical. It can be created, for example, by drilling a glass bore. The radiation source 2 is arranged within the opening. The radiation source 2 is arranged such that it can couple the IR radiation 3 directly via the edge region of the optical waveguide 1. The recess 12 is arranged in an edge region of the disk 6 adjacent to the lower edge U.The outer pane is connected to the first surface i of the glass pane 6 via the spacer (not shown here). The first surface i of the pane 6 is therefore not exposed to the external environment.

[0089] In Figure 5, the optical waveguide 1 has an IR-reflecting coating 4 on its first surface I. The IR-reflecting coating 4 extends over the entire first surface I of the optical waveguide 1, i.e., is applied over its entire surface. The IR-reflecting coating 4 comprises, for example, one or more silver layers. The coating 4 largely prevents IR radiation 3 from being coupled out at the first surface I of the optical waveguide 1 and thus reaching the external environment 9. The optical waveguide 1 is also connected to an outer pane 11 in the edge region via a spacer 7. The spacer 7 is frame-like and arranged in the edge region between the optical waveguide 1 and the outer pane 11 in order to keep them essentially plane-parallel at a defined distance from one another. The spacer is made, for example, of aluminum.It is preferably in contact with the optical waveguide 1, or the IR-reflecting coating 4 applied to the optical waveguide 1, and the outer pane 11 via a sealing compound. In the marginal space between the panes, which is open to the outside, an external sealing compound based on silicone, for example, is filled. The inner space between the panes, which is delimited and enclosed by the optical waveguide 1, the outer pane 11 and the spacer, is filled with argon, for example. The outer pane 11 is, for example, a glass pane made of soda-lime glass with a thickness of 3.5 mm. The outer pane 11 has a second surface iv exposed to the external environment 9 and a first surface iii facing the space between the optical waveguide 1 and the outer pane 11.

[0090] Figure 6 shows an absorption spectrum of water in the liquid state. The diagram shows that water molecules have a particularly high absorption coefficient, for example at a wavelength of approximately 3 pm. In a preferred embodiment, a radiation source in the IR wavelength range from A = 2.5 pm to A = 3.3 pm, particularly preferably from A = 2.9 pm to A = 3.1 pm, is therefore used for the refrigerator glazing, since the absorption and excitation of the water molecules, and thus the resulting heating and evaporation, is particularly high in this preferred wavelength range. At the same time, the optical fiber preferably has a transmission in the wavelength range from A = 2.9 pm to A = 3.1 pm of over 70%, in particular at approximately A = 3.0 pm of approximately 85%, so that the radiation energy can be used efficiently for defrosting and evaporating water in the corresponding areas.

[0091] List of reference symbols:

[0092] 1 optical fiber

[0093] 2 Radiation source

[0094] 3 IR radiation

[0095] 4 IR-reflective coating

[0096] 5 IR mirror layer

[0097] 6 slices

[0098] 7 spacers

[0099] 8 Refrigerator interior

[0100] 9 external environment

[0101] 10 Water

[0102] 11 outer pane

[0103] 12 Recess

[0104] 13 Moisture detector

[0105] 14 Control unit

[0106] 100 refrigerator glazing

[0107] 101 Refrigerator door

[0108] 102 Cooling device i first surface of the pane 6 ii second surface of the pane 6 iii first surface of the outer pane 11 iv second surface of the outer pane 11

[0109] I first surface of the optical fiber 1

[0110] II second surface of the optical waveguide 1

[0111] 51 first page edge

[0112] 52 second side edge

[0113] O top edge

[0114] U bottom edge

[0115] XX' cutting line

Claims

Patent claims 1. Refrigerator glazing (100), comprising at least one optical waveguide (1) for conducting radiation (3) in the IR wavelength range with a first surface (I) and a second surface (II), at least one radiation source (2) for radiation (3) in the IR wavelength range from λ = 1.3 pm to 3.5 pm, an outer pane (11) and a spacer (7) which is arranged between the optical waveguide (1) and the outer pane (11), wherein the radiation source (2) is arranged relative to the optical waveguide (1) in such a way that the radiation (3) emitted by the radiation source (2) can be coupled into the optical waveguide (1).

2. Refrigerator glazing (100) according to claim 1, wherein the radiation source (2) comprises at least one LED, OLED and / or a laser, preferably at least one LED.

3. Refrigeration device glazing (100) according to claim 1 or 2, wherein the radiation source (2) can emit radiation (3) in the IR wavelength range from A = 2.5 pm to A = 3.3 pm, preferably from A = 2.6 pm to A = 2.9 pm.

4. Refrigerator glazing (100) according to one of claims 1 to 3, wherein the optical waveguide (1) is designed as a disc and the second surface (II) of the optical waveguide (1) is intended to be a surface exposed to the refrigerator interior (8), and the spacer (7) connects the outer disc (11) and the optical waveguide (1) to one another.

5. Refrigeration appliance glazing (100) according to one of claims 1 to 4, wherein the optical waveguide (1) is a glass pane made of soda-lime glass, borosilicate glass, quartz glass or aluminosilicate glass.

6. Refrigerator glazing (100) according to claim 4 or 5, wherein an IR-reflecting coating (4) is applied to the first surface (I) of the optical waveguide (1) and extends over at least 80% of the area of ​​the optical waveguide (1).

7. Refrigerator glazing (100) according to claim 6, wherein the IR-reflecting coating (4) comprises at least one metallic layer.

8. Refrigeration appliance glazing (100) according to one of claims 1 to 3, wherein the optical waveguide (1) is applied to a surface (ii) of a pane (6) as a coating and contains, preferably consists of, silicon nitride and / or titanium dioxide.

9. Refrigeration appliance glazing (100) according to one of claims 1 to 8, wherein the radiation source (2) is arranged on at least a portion of a circumferential edge surface (S1, S2, O, U) of the optical waveguide (1).

10. Refrigeration device glazing (100) according to one of claims 1 to 8, wherein an IR radiation-reflecting prism film (5) is applied to the first surface (I) or the second surface (II) of the optical waveguide (1) and wherein the Radiation source (2) is arranged in relation to the IR radiation-reflecting prism film (5) in such a way that the emitted radiation (3) can be coupled into the optical waveguide (1) by means of reflection at the IR radiation-reflecting prism film (5).

11. Refrigerator glazing (100) according to one of claims 1 to 8, wherein the radiation source (2) is arranged in a recess (12) of the optical waveguide (1).

12. A refrigerator (102) comprising a refrigerator glazing (100) according to any one of claims 1 to 11.

13. The refrigerator (102) of claim 12, further comprising a refrigerator door (101) having the refrigerator glazing (100).

14. Cooling device (102) according to claim 12 or 13, further comprising a moisture detector (13) for detecting water (10) on the first surface (I) and / or the second surface (II) of the optical waveguide (1) and a control unit (14), wherein the moisture detector (13) is configured to send a signal A to the control unit (14) when water (10) is present on the first surface (I) and / or the second surface (II) of the optical waveguide (1), wherein the control unit (14) is configured such that, at least upon receipt of signal A, it electronically controls the radiation source (2) so that the radiation source (2) emits radiation (3) which is coupled into the optical waveguide (1).

15. The refrigeration device (102) according to claim 13 or 14, further comprising a motion sensor and a control unit (14), wherein the motion sensor is configured to send a signal B to the control unit (14) when the refrigeration device door (101) is opened, wherein the control unit (14) is configured to electronically control the radiation source (2) at least upon receipt of signal B, so that the radiation source (2) emits radiation (3) which is coupled into the optical waveguide (1).

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