WO2021151664A1

WO2021151664A1 - Hob device

Info

Publication number: WO2021151664A1
Application number: PCT/EP2021/050540
Authority: WO
Inventors: Jesús CEAMANOS GAYA; Ana Elduque Viñuales; Patricia GOMEZ BACHILLER; Javier Lasobras Bernad; Damaso Martin Gomez; Marta OSTA LOMBARDO; Pilar Perez Cabeza; Fabian Puls; Julio Rivera Peman; Jesús Ricardo Ruiz Gracia; Ander Villate Robles
Original assignee: BSH Hausgeräte GmbH
Priority date: 2020-01-31
Filing date: 2021-01-13
Publication date: 2021-08-05
Also published as: EP4098079A1

Abstract

The invention relates to a hob device (10a-b), in particular an induction hob device, comprising at least one hob plate (12a-b), comprising at least one light wave guide unit (16a-b) arranged on an underside (14a-b) of the hob plate (12a-b) and having at least one light wave guide (18a-b) for guiding light, in turn having a base body (34a-b), and at least one light outlet element (20a-b) which is provided to define a light-outlet surface for letting light out of the light wave guide (18a-b). According to the invention, in order to increase user comfort, the light-outlet element (20a-b) is arranged on a side of the light wave guide (18a-b) facing the hob plate (12a-b).

Description

Hob device

The invention relates to a hob device according to the preamble of claim 1.

From US 2019/246832 A1 it is known to equip hobs with optical waveguides arranged under a hob plate of the hob which, when viewed perpendicular to the hob plate, surround a heating element of a cooking zone and to mark the cooking zone over an entire side of the hob plate Light waveguide emit light.

The object of the invention is in particular, but not limited to, to provide a generic device with improved properties with regard to De sign possibilities. The object is achieved according to the invention by the features of claim 1, while advantageous configurations and developments of the invention can be found in the subclaims.

The invention is based on a hob device, in particular an induction hob device, with at least one hob plate, with at least one optical waveguide unit arranged on an underside of the hob plate, which at least one optical waveguide for a line of light, which has a base body, and at least one light exit element has, which is provided to define a light exit surface for an exit of the light from the optical waveguide.

It is proposed that the light exit element is arranged, preferably completely, on a side of the optical waveguide facing the hob plate.

Such a configuration can in particular enable new design options for lighting the hob plate. In particular, different optical waveguides of the same shape with different light exit surfaces can be provided. The aesthetics of the lighting of a hob having the hob device can advantageously be improved.

A “hob device”, in particular an “induction hob device”, should in particular mean at least one part, in particular a subassembly, of a Cooktop are understood, wherein in particular accessory units for the cooktop can also be included, such as, for example, a sensor unit for external measurement of a temperature of a cookware and / or an item to be cooked. The hob can in particular be designed as a radiant hob, a resistance heating hob and / or as a gas hob. The hob is preferably designed as an induction hob. In particular, the hob device, in particular the induction hob device, can also encompass the entire hob.

The hob device preferably has at least one light source unit for providing the light. A “light source unit” is to be understood in particular as a unit which has at least one light source and which provides light, in particular visible light, in at least one operating state, in particular by means of the light source. In particular, the light source unit has at least two, in particular at least four, advantageously at least eight, particularly advantageously at least twelve and preferably a plurality of light sources. It would be conceivable that exactly one light source is assigned to the optical waveguide, preferably several light sources are assigned to the optical waveguide. At least one light source of the light source unit could, for example, be designed as a, preferably backlit, display unit, in particular as a matrix display unit, preferably as an LCD display, or as an OLED display. In particular, at least one light source of the light source unit, advantageously at least a large part of the light sources, preferably all of the light sources of the light source unit, is designed as an LED. In particular, the light sources of the light source unit form at least one RGBW LED system. “Visible light” is to be understood as meaning, in particular, electromagnetic radiation from a wavelength range from 380 nm to 780 nm. In particular, a beam direction of the light provided by the light source faces the optical waveguide. The hob device preferably has at least one light wave coupling unit which has at least one light wave coupling element for coupling the light provided by the light source into the optical waveguide. The light wave coupling element can in particular be designed as a light adapter known to the person skilled in the art, for example a silicone light adapter. It would be conceivable for the light source, in an assembled state, to be arranged on a side of the optical waveguide facing away from the hob plate. In the assembled state, the light source is preferably spaced apart horizontally from the optical waveguide; Field plate aligned side of the optical waveguide arranged. In particular, the optical waveguide in the assembled state is surrounded by at least two, particularly advantageously at least four, light sources when viewed perpendicularly to the hob. In particular, the direction of the rays of the light provided by the light source is aligned parallel to the hob plate.

An “optical waveguide unit” is to be understood as meaning, in particular, a unit which comprises at least one optical waveguide and which is provided in at least one operating state to transmit light, in particular visible light, advantageously the light provided by the light source, in particular in a targeted and / or directed manner, from a first region, in particular from the light source, into at least one second region that is different and / or spaced apart from the first. In particular, the optical waveguide unit is intended to guide the light provided by the light source for illuminating the hob plate, in particular of cooking zones and / or user interface markings on the hob plate, in the direction of the hob plate. An "optical waveguide" is to be understood in particular as an element which, in at least one operating state, includes electromagnetic radiation, in particular visible light and / or infrared radiation, advantageously both visible light and infrared radiation, in the longitudinal direction and / or along a main street Coverage plane of the optical waveguide is transmitted, in particular transported, preferably via total reflections within the optical waveguide. A "direction of longitudinal extent" of an object is to be understood in particular as a direction which is parallel to a longest side of a smallest imaginary geometric cuboid that just completely surrounds the object. A “main extension plane” of an object is to be understood in particular as a plane which is parallel to a largest side surface of a smallest imaginary cuboid, which just completely surrounds the object, and in particular runs through the center of the cuboid. In particular, the optical waveguide is arranged in an assembled state between the hob plate and a heating element, in particular an inductor, of the cooking field device. It would be conceivable that the optical waveguide is designed as an optical cable. The optical waveguide is in particular formed in one piece. "In one piece" is to be understood in particular to be at least cohesively connected, for example by a coating process, an adhesive process, an injection process and / or another process that appears sensible to a person skilled in the art, and / or in particular be understood to be formed in one piece, such as, for example, by production from a cast and / or by production in a one-component or multi-component injection molding process and advantageously from a single blank. In particular, in at least one operating state, the optical waveguide prevents the entry and / or exit of at least electromagnetic radiation outside the light wave exit surface in at least substantially perpendicular directions to the longitudinal extension direction and / or at least substantially perpendicular to the main extension plane of the optical waveguide, at least substantially. The term "substantially perpendicular" is intended to define in particular an alignment of a direction relative to a reference direction, the direction and the reference direction, particularly viewed in a plane, encompassing an angle of 90 ° and the angle including a maximum deviation of, in particular, less than 8 °, advantageously less than 5 ° and particularly advantageously less than 2 °. Advantageously, the light waveguide has at least one base body that is at least partially, in particular completely, transparent to light and at least one element that is at least partially, in particular completely, opaque to light, for example an opaque or reflective coating of the base body. The fact that an element is “opaque” is to be understood in particular as meaning that at least one side of the element, preferably all sides of the element, are completely reflective and / or absorbent for light incident into the element. Alternatively, the optical waveguide could be formed entirely by a base body which is reflective, in particular totally reflective, at least for the light on one side of the base body facing the hob plate and one facing away from the hob plate. It would be conceivable that the optical waveguide unit has a multiplicity of optical waveguides, preferably the optical waveguide unit has exactly one optical waveguide.

It would be conceivable that the light exit element could be arranged at a distance from the optical waveguide or fastened detachably to the optical waveguide, for example by a snap connection and / or latching connection and / or plug connection and / or screw connection.

The light wave exit surface is advantageously a partial surface of the side of the optical waveguide facing the hob plate. In particular, the light exit element is plate-shaped. The fact that an element is "plate-shaped" is to be understood in particular that the element has a thickness that corresponds to a maximum of 50%, in particular a maximum of 20%, advantageously a maximum of 10%, preferably a maximum of 5%, of a length and a width of the element. In particular, the light exit element differs from, in particular opaque and / or reflective, coatings and / or sheaths which are arranged on a side of the optical waveguide opposite the hob plate and / or along a circumference of the optical waveguide.

“Provided” is to be understood as meaning, in particular, specially designed and / or equipped. The fact that an object is provided for a specific function is to be understood in particular to mean that the object fulfills and / or executes this specific function in at least one application and / or operating state.

It would be conceivable that the optical waveguide is rod-shaped and / or cubic. In order to increase space efficiency and the size of a region of the hob plate covered by the optical waveguide, it is proposed that the optical waveguide be plate-shaped. The optical waveguide preferably has at least one, preferably at least two, in particular opposite sides, which have a flat, especially smooth surface. The optical waveguide is preferably free of concave outer surfaces. For example, the optical waveguide could be designed as an annular disk. The optical waveguide is preferably designed as a circular disk or a square disk, in particular a rectangular disk. In particular, the Lichtwel lenleiter covers a portion of the underside of the hob plate; alternatively, the optical waveguide could cover the entire underside of the hob plate. In this way, in particular, a simple and compact arrangement of the optical waveguide below a region of the hob plate to be illuminated can be achieved.

It is further proposed that the light exit element and the optical waveguide in particular are at least partially formed in one piece and the light exit element has at least one coating of the base body. Alternatively or additionally, the light exit element could have at least one recess and / or highlight and / or roughened surface of the base body. In particular, the light exit element could be produced by at least one etching process and / or cutting process carried out on the base body. The fact that the light exit element and the light waveguide are "at least partially in one piece" should be understood in particular to mean that the light exit element and the light waveguide have at least one Have a common element, which is a component, in particular functionally important component, of the light exit element and the optical waveguide. In particular, the coating of the base body serves exclusively to guide the light. The light exit element advantageously additionally has at least one further coating of the base body, which is different from the coating in particular with regard to a function. Alternatively, the light exit element can only have the further coating. In particular, the coating has at least one recess which is used to define the light exit surface. The further coating is preferably arranged in the recess. As a result, the space efficiency in particular can be further increased and the production of the hob device can be simplified. Advantageously, at least part of the light exit element can be produced at the same time during the production of the optical waveguide.

It would be conceivable that the hob device has at least one separate diffuser element, which could be arranged, for example, between the light exit element and the hob plate and is provided to provide diffuse illumination of the hob plate. In order to further simplify installation space efficiency and manufacture of the cooking field device, it is proposed that the light outlet element have at least one diffuser element. A “diffuser element” is to be understood in particular as an element which is provided to convert light incident into the element into diffuse illumination. “Diffuse lighting” is to be understood as meaning, in particular, lighting whose radiation output varies over a period of at least one hour directly on a surface of the diffuser element facing an area to be illuminated, on average, in particular homogeneously over a spatial angular range facing the area to be illuminated of at least TT, preferably of at least 3 / 2p and particularly before geous of 2TT, distributed. It would be conceivable that the diffuser element is conical and / or rod-shaped and / or semi-tubular and / or hemispherical. Furthermore, it would be conceivable that the diffuser element is designed as a recess and / or a prominence and / or a roughened surface of the light exit element and / or the base body. It would also be conceivable that the diffuser element is designed as an adhesive element, for example a silicone adhesive, which attaches the optical waveguide to the underside of the hob plate. The diffuser element is preferably designed in the form of a plate; the diffuser element is particularly preferably designed as a coating. educated. As a result, the use of additional diffuser elements can in particular be dispensed with.

It is also proposed that the light exit element define a light barrier surface to prevent the light from exiting from the optical waveguide. A “light barrier surface” is to be understood in particular as a surface which is opaque to light at least in places and / or at least for certain angles of incidence and / or at least for certain light frequencies and preferably for light. It would be conceivable that the light exit element and / or the base body have at least one recess and / or highlight and / or roughened surface which defines the light barrier surface. The light exit element preferably has at least one coating, preferably the coating, which firmly defines the light barrier surface. In this way, the light exit surface in particular can be defined in a simple manner.

It would be conceivable that the light barrier surface completely absorbs the light. In order to simplify guiding the light, it is proposed that the light exit element, in particular the light barrier surface, be at least partially reflective. The fact that the light exit element is “at least partially reflective” should in particular be understood to mean that the light exit element is totally reflective at least in places and / or at least for certain angles of incidence and / or at least for certain light frequencies and preferably for the light. The coating of the optical waveguide is advantageously designed as a reflective coating. Particularly advantageously, the optical waveguide has on a side of the Lichtwel lenleiters facing away from the hob plate at least one further reflective coating of the base body, which preferably extends over the entire side of the base body facing away from the hob plate. In particular, this allows the light to be guided by Totalre flexion on opposite sides of the optical waveguide.

It would be possible for the light exit surface and the light barrier surface to be arranged separately from one another, for example the light exit surface and the light barrier surface could be separated from one another by at least one opaque coating on the light exit element. In order to simplify the definition of the light exit surface, it is proposed that the light exit surface and the light barrier surface jointly form a contiguous area of the side of the light wave guide facing the hob plate. ters form. The contiguous area advantageously extends over the entire side of the optical waveguide facing the hob plate. The light exit surface is advantageously defined by recesses in the light barrier surface. Particularly before given, the diffuser element of the light exit element extends over the entire light exit surface. It would be conceivable that the diffuser element is formed as the adhesive element and is arranged in the recesses of the light barrier surface. The diffuser element is preferably designed as the further coating and is arranged in the recesses of the light barrier surface. In this way, diffuse lighting can be provided in predefined areas of the hob plate in a particularly simple manner. A simple and space-saving design of the light exit surface and the light barrier surface can advantageously be achieved.

In addition, it is proposed that the side of the base body facing the hob plate is at least partially translucent. The fact that the side of the base body facing the hob plate is "at least partially translucent" is to be understood in particular as the side of the base body facing the hob plate at least in places and / or at least for certain angles of incidence and / or at least for certain light frequencies and is preferably transparent to light. In particular, the optical waveguide has at least one reflective coating on the side of the base body facing the hob plate and on one side of the base body facing away from the hob plate. In this way, in particular, additional elements of the light exit element for allowing the light to pass through the side of the base body facing the hob plate can be dispensed with.

In a further aspect of the invention it is proposed that the side of the base body facing the hob plate is at least partially reflective. In particular, the base body of the optical waveguide completely forms the optical waveguide. In particular, the base body is totally reflective for the light on the side of the base body facing the hob plate and facing away from the hob plate. For example, the base body could have recesses and / or protrusions and / or roughened surfaces on both sides, which in particular extend completely over both sides. In this way, in particular, simple production of the optical waveguide can be achieved. It is advantageous to dispense with reflective coatings on the optical waveguide. It would be conceivable that the base body has at least one partial surface which is transparent to light. For example, the partial surface could be formed as a recess and / or highlight and / or roughened partial surface of the base body. In order to enable the light exit surface to be easily defined, it is proposed that the hob device have at least one contact element which, in an assembled state, contacts the side of the light waveguide facing the hob plate, a refractive index of the light exit element differing from a refractive index of the contact element. For example, the contact element could consist of air, in particular the contact element can be designed as the adhesive element or the hob plate. In the assembled state, the side of the optical waveguide assigned to the hob plate preferably makes direct contact with the hob plate, particularly preferably the refractive index of the light exit element differs from a refractive index of the hob plate. In particular, the light exit element serves to cancel the total reflection of the light on the side of the base body facing the cooking field plate. In particular, the light outlet element is designed as the further coating of the base body. The light exit element is advantageously designed as a diffusion element. As a result, the light exit element can be produced by simply coating the base body. The light exit element can advantageously be printed onto the base body.

It would be conceivable that the optical waveguide unit is fastened to the underside of the hob plate by means of at least one snap connection and / or screw connection and / or plug connection and / or latching connection. In order to enable simple attachment of the optical waveguide unit, it is proposed that the optical waveguide unit be glued to the underside of the hob plate. In particular, the lightwave conductor is glued to the underside of the hob plate by means of at least one adhesive element, which could have, for example, a silicone adhesive and / or an adhesive tape, in particular double-sided adhesive tape, and / or other types of adhesive elements known to those skilled in the art. As a result, the optical waveguide unit in particular can be attached in a simple manner to conventional hob plates.

Finally, a hob, in particular an induction hob, with at least one hob device is proposed. In particular, user convenience can be increased as a result. The aesthetics of the lighting of the hob Device having hob can be improved. New designs and / or functions of the lighting can be made possible in a particularly advantageous manner.

The hob device is not intended to be restricted to the application and embodiment described above. In particular, the hob device can have a number of individual elements, components and units that differs from a number of individual elements, components and units mentioned herein in order to fulfill a mode of operation described herein.

Further advantages emerge from the following description of the drawings. In the drawings, two embodiments of the invention are shown. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Show it:

Fig. 1 A hob with a hob device in a plan view,

2 shows the hob in a top view with an optical waveguide unit of the hob device,

FIG. 3 shows a sectional illustration of the hob along a section line A-A from FIG. 2,

Fig. 4 shows a further embodiment of a hob with a Kochfeldvor direction in a plan view and

FIG. 5 shows a sectional illustration of the hob along a section line B-B from FIG. 4.

In the figures, only one object of multiple existing objects is provided with a reference symbol.

Figure 1 shows a hob 32a. The hob 32a is designed as an induction hob. The hob 32a has a cooking zone 36a. The cooking zone 36a is arranged in a center of the hob 32a. The hob 32a has a hob device 10a, which is shown in more detail in FIG. The hob device 10a is used to illuminate the cooking zone 36a. As an alternative or in addition, the hob 32a could have further hob devices, which in particular could serve to illuminate further cooking zones of the hob 32a. The hob device 10a has a hob plate 12a. The hob plate 12a consists of glass ceramic. Alternatively, the hob plate 12a could consist of other common materials for hob plates known to the person skilled in the art. The hob device 10a has an optical waveguide unit 16a, which is shown in more detail in FIG. 3 in a sectional illustration. The optical waveguide unit 16a is arranged on an underside 14a of the hob plate 12a. The optical waveguide unit 16a is glued to the underside 14a of the hob plate 12a. The optical waveguide unit 16a is glued to the underside 14a of the hob plate 12a by means of an adhesive element (not shown). The adhesive element is designed as a silicone adhesive. Alternatively, the adhesive element could be designed as a double-sided adhesive tape or other adhesive elements known to the person skilled in the art. The optical waveguide unit 16a has an optical waveguide 18a. Alternatively or additionally, the optical waveguide unit 16a could have further optical waveguides. The optical waveguide 18a is used to conduct light.

The hob device 10a has a light source unit 38a. The light source unit 38a has four light sources 40a. The light sources 40a are provided for providing light. The light sources 40a are arranged on four opposite sides of the optical waveguide 18a in pairs. The light sources 40a are arranged on sides of the optical waveguide 18a that are oriented perpendicular to the hob plate 12a. As an alternative or in addition, the light source unit 38a could have any other number of light sources 40a and an arrangement of the light sources 40a. The light sources 40a provide light. The light sources 40a each define a direction of radiation of the light. The directions of radiation face the optical waveguide 18a. In the following, for the sake of clarity, the expression “the light provided by the light sources 40a” is abbreviated by the expression “the light”.

The optical waveguide 18a is plate-shaped. The optical waveguide 18a is circular disk-shaped. The optical waveguide 18a has a base body 34a. A side of the base body 34a facing the hob plate 12a is transparent to light. The base body 34a is completely transparent to light. The optical waveguide 18a has a first reflective coating 42a. The base body 34a is coated with the first reflective coating 42a. The first reflective coating 42a is arranged on a side of the optical waveguide 18a facing away from the hob plate 12a. The first reflective coating 42a extends over the whole of the hob plate 12a facing away from the side of the optical waveguide 18a. The first reflective coating 42a is used to guide the light within the optical waveguide 18a.

The optical waveguide 18a has a second reflective coating 26a. The base body 34a is coated with the second reflective coating 26a. The second reflective coating 26a is arranged on the side of the optical waveguide 18a facing the hob plate 12a. The second reflective coating 26a has recesses 44a. The second reflective coating 26a is used to guide the light within the optical waveguide 18a.

The hob device 10a has a light exit element 20a. The light exit element 20a defines a light exit surface for an exit of the light from the Lichtwel lenleiter 18a. The light exit element 20a is arranged on the side of the optical waveguide 18a facing the hob plate 12a. The light exit element 20a is partially formed in one piece with the optical waveguide 18a. The light exit element 20a is partially reflective for the light. The light exit element 20a and the light waveguide 18a together have the second reflective coating 26a. The second reflective coating 26a is used to define the light exit surface. The second reflective coating 26a defines a light barrier surface for preventing the light from escaping from the optical waveguide 18a. The recesses 44a of the second reflective coating 26a define the light exit surface.

The light exit surface and the light barrier surface together form a coherent surface 30a of the side of the light waveguide 18a facing the hob plate 12a. The contiguous surface 30a extends over the entire side of the optical waveguide 18a facing the cooking field plate 12a.

The light exit element 20a has a diffuser element 28a. The diffuser element 28a is designed as a further coating of the base body 34a. The diffuser element 28a is arranged in the recesses 44a of the second reflective coating 26a. The diffuser element 28a is used to provide diffuse illumination of the hob plate 12a.

In Figures 4 and 5, a further embodiment of the invention is shown. The following descriptions are essentially limited to the differences between the exemplary embodiments, with components and features that remain the same and functions can be referred to the description of the embodiment of Figures 1 to 3 ver. To distinguish the exemplary embodiments, the letter a in the reference symbols of the exemplary embodiment in FIGS. 1 to 3 is replaced by the letter b in the reference symbols of the exemplary embodiment in FIGS. 4 and 5. With regard to components with the same designation, in particular with regard to components with the same reference symbols, reference can in principle also be made to the drawings and / or the description of the exemplary embodiment in FIGS. 1 to 3.

Figures 4 and 5 show a further embodiment of a hob 32b with a hob device 10b. The hob device 10b has a hob plate 12b. The hob device 10b has a light source unit 38b. The light source unit 38b has a plurality of light sources 40b. The light sources 40b are arranged in a row. The light sources 40b are spaced apart horizontally from the hob plate 12b.

The hob device 10b has an optical waveguide unit 16b. The optical waveguide unit 16b has an optical waveguide 18b. The optical waveguide 18b is designed as a rectangular disk. The optical waveguide 18b extends over an entire underside 14b of the hob plate 12b. The optical waveguide 18b has a base body 34b. A side of the base body 34b facing the hob plate 12b is totally reflective for the light. A side of the base body 34b facing away from the hob plate 12b is totally reflective for the light.

The base body 34b has a first reflective coating 42b. The first reflective coating 42b is arranged on a side of the base body 34b oriented perpendicular to the hob plate 12b. The first reflective coating 42b serves to prevent light provided by the light source 40b from escaping through the side of the base body 34b that is oriented perpendicular to the hob plate 12b.

The hob device 10b has a light exit element 20b. The light exit element 20b has a light-extracting coating 22b of the base body 34b.

The light-extracting coating 22b forms the light exit element 20b completely. The light-extracting coating 22b is designed as a diffuser element 28b.

The hob device 10b has a contact element 24b. The contact element 24b makes contact with the side of the optical waveguide 18b facing the hob plate 12b. That Contact element 24b consists of air. The light-extracting coating 22b has a refractive index which is different from a refractive index of air. Alternatively, the contact element 24b could be designed as an adhesive element or as the hob plate 12b. The light-extracting coating 22b serves to cancel a total reflection of the light on the side of the base body 34b facing the hob plate 12b.

Reference number

10 hob device

12 hob plate

14 bottom

16 fiber optic unit

18 fiber optic cables

20 light exit element

22 light-extracting coating

24 contact element

26 second reflective coating

28 diffuser element

30 contiguous area

32 hob

34 base body

36 cooking zone

38 light source unit

40 light source

42 first reflective coating 44 recess

Claims

Expectations

1. Hob device (10a-b), in particular induction hob device, with at least one hob plate (12a-b), with at least one optical waveguide unit (16a-b) arranged on an underside (14a-b) of the hob plate (12a-b), which at least an optical waveguide (18a-b) for a line of light, wel cher has a base body (34a-b), and at least one light exit element (20a-b), which is provided, a light exit surface for an exit of the light from the optical waveguide (18a-b), characterized in that the light exit element (20a-b) is arranged on a side of the optical waveguide (18a-b) facing the hob plate (12a-b).

2. hob device (10a-b) according to claim 1, characterized in that the optical waveguide (18a-b) is plate-shaped.

3. Hob device (10a-b) according to claim 1 or 2, characterized in that the light exit element (20a-b) has at least one coating (22a, 26b, 42b) of the base body (34a-b).

4. hob device (10a-b) according to one of the preceding claims, characterized in that the light exit element (20a-b) has at least one diffuser element (28a-b).

5. hob device (10a) according to any one of the preceding claims, characterized in that the light exit element (20a) defi ned a light barrier surface to prevent the light from escaping from the optical waveguide (18a).

6. hob device (10a) according to claim 5, characterized in that the light exit element (20a) is at least partially reflective.

7. hob device (10a) according to claim 5 or 6, characterized in that the light exit surface and the light barrier surface together form a coherent surface (30a) of the hob plate (12a) facing side of the optical waveguide (18a).

8. hob device (10a) according to any one of the preceding claims, characterized in that one of the hob plate (12a) facing side of the Ba siskörpers (34a) is at least partially translucent.

9. hob device (10b) according to one of the preceding claims, characterized in that one of the hob plate (12b) facing side of the base body (34b) is at least partially reflective.

10. Hob device (10b) according to claim 9, characterized in that at least one contact element (24b) which, in an assembled state, contacts the side of the optical waveguide (18b) facing the hob plate (12b), a refractive index of the light exit element (20b) differs from a refractive index of the contact element (24b).

11. Hob device (10a-b) according to one of the preceding claims, characterized in that the optical waveguide unit (16a-b) is glued to the underside (14a-b) of the hob plate (12a-b).

12. hob (32a-b) with at least one hob device (10a-b) according to one of the preceding claims.