Hob device

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

[0001] The invention relates to a cooktop device according to the preamble of claim 1.

[0002] US patent 2019 / 246 832 A1 discloses the use of optical fibers to equip cooktops with fiber optic cables arranged beneath the cooktop surface. These fiber optic cables, when viewed perpendicular to the cooktop surface, surround a heating element of each cooking zone and emit light along the entire side of the optical fiber facing the cooktop surface to mark the cooking zone. Further cooktop devices are disclosed in DE 44 05 610, JP H07 312280, EP 3 225 918, JP 2003 151741, and JP 2014 044809.

[0003] The object of the invention is, in particular but not limited to, providing a generic device with improved design features. This object is achieved according to the invention by the features of claim 1, while advantageous embodiments and further developments of the invention can be found in the dependent claims.

[0004] The invention relates to 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 has at least one optical waveguide for a transmission of light, which has a base body, and at least one light emission element, which is provided to define a light emission surface for the emission of light from the optical waveguide.

[0005] It is proposed that the light emission element be arranged, preferably completely, on one side of the optical waveguide facing the hob plate.

[0006] This design opens up new design possibilities for cooktop lighting. Specifically, it allows for the use of different optical fibers of the same shape with varying light-emitting surfaces. This can advantageously improve the aesthetics of the lighting on a cooktop that incorporates the hob unit.

[0007] The term "cooktop device," and in particular "induction cooktop device," is understood to mean at least a part, especially a subassembly, of a cooktop, and may also include accessory units for the cooktop, such as a sensor unit for externally measuring the temperature of cookware and / or food being cooked. The cooktop may be designed as a radiant cooktop, a resistance heating cooktop, and / or a gas cooktop. Preferably, the cooktop is designed as an induction cooktop. In particular, the cooktop device, especially the induction cooktop device, may also comprise the entire cooktop.

[0008] Preferably, the cooktop device has at least one light source unit for providing light. A "light source unit" is understood to be, in particular, a unit that has at least one light source and that provides light, especially visible light, in at least one operating state, particularly 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 is conceivable that exactly one light source is assigned to the optical fiber; preferably, several light sources are assigned to the optical fiber. At least one light source of the light source unit could, for example, be designed as a display unit, preferably backlit, 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 majority of the light sources, preferably all 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 understood to mean, in particular, electromagnetic radiation from a wavelength range of 380 nm to 780 nm. In particular, one direction of the light provided by the light source is directed towards the optical waveguide. Preferably, the cooktop device has at least one optical wave coupling unit, which has at least one optical wave coupling element for coupling the light provided by the light source into the optical waveguide. The optical wave coupling element can, in particular, be designed as a light adapter known to those skilled in the art, for example, a silicone light adapter.It is conceivable that, in the assembled state, the light source is arranged on the side of the optical fiber facing away from the cooktop. Preferably, the light source is horizontally spaced from the optical fiber in the assembled state; more preferably, the light source is arranged on a side of the optical fiber oriented perpendicular to the cooktop. In particular, when viewed perpendicular to the cooktop, the optical fiber in the assembled state is surrounded by at least two, and more advantageously at least four, light sources. The direction of light emitted by the light source is particularly parallel to the cooktop.

[0009] The term "optical waveguide unit" shall be understood to mean, in particular, a unit comprising at least one optical waveguide and designed, in at least one operating state, to direct light, particularly visible light, advantageously the light provided by the light source, in a targeted and / or directed manner, from a first area, particularly from the light source, to at least one second area that is different from and / or spaced apart from the first. In particular, the optical waveguide unit is designed to direct the light provided by the light source towards the cooktop for illumination of the cooktop, in particular of cooking zones and / or user interface markings of the cooktop.An "optical waveguide" shall be understood to be, in particular, an element which, in at least one operating state, transmits electromagnetic radiation, especially visible light and / or infrared radiation, advantageously both visible light and infrared radiation, in the longitudinal direction and / or along a principal plane of extension of the optical waveguide, preferably via total internal reflection within the optical waveguide. The "longitudinal direction" of an object shall be understood to be, in particular, a direction which is aligned parallel to a longest side of the smallest imaginary geometric cuboid that just completely encloses the object.A "principal extension plane" of an object is understood to be, in particular, a plane that is parallel to a major side face of the smallest imaginary cuboid that just completely encloses the object, and especially one that passes through the center of the cuboid. The optical waveguide is arranged in an assembled state between the cooktop and a heating element, in particular an inductor, of the cooktop device. It is conceivable that the optical waveguide is designed as an optical cable. The optical waveguide is, in particular, formed in one piece.The term "one-piece" is to be understood in particular as being at least materially bonded, for example by a coating process, an adhesive process, an injection molding process and / or another process that would appear appropriate to a person skilled in the art, and / or in particular as being formed in one piece, such as by being manufactured from a single casting and / or by being manufactured using a single- or multi-component injection molding process, and advantageously from a single blank. In particular, the optical waveguide, in at least one operating state, prevents the entry and / or exit of at least electromagnetic radiation outside the optical wave exit surface in directions oriented at least substantially perpendicular to the longitudinal direction and / or at least substantially perpendicular to the principal plane of extension of the optical waveguide.The term "essentially perpendicular" here is intended to define, in particular, an orientation of a direction relative to a reference direction, wherein the direction and the reference direction, especially when considered in a plane, enclose an angle of 90° and the angle has a maximum deviation of, in particular, less than 8°, advantageously less than 5°, and most advantageously less than 2°. Advantageously, the optical waveguide comprises at least one base body that is at least partially, and in particular completely, transparent to light, and at least one element that is at least partially, and in particular completely, opaque to light, for example, an opaque or reflective coating of the base body.The term "opaque" for an element means, in particular, that at least one side of the element, preferably all sides of the element, is completely reflective and / or absorbent of light incident on the element. Alternatively, the optical waveguide could be formed entirely by a base body which is reflective, in particular totally reflective, at least with respect to the light on one side facing the cooktop and one side facing away from the cooktop. The optical waveguide unit could have a plurality of optical waveguides; preferably, the optical waveguide unit has exactly one optical waveguide. The light-emitting element could be spaced apart from the optical waveguide or detachably attached to the optical waveguide, for example, by a snap-fit ​​connection, a locking connection, a plug connection, or a screw connection.

[0010] Advantageously, the light wave exit surface is a partial surface of the side of the optical waveguide facing the cooktop. The light exit element is plate-shaped. The term "plate-shaped" refers in particular to the fact that the element has a thickness that corresponds to a maximum of 50%, particularly a maximum of 20%, advantageously a maximum of 10%, and preferably a maximum of 5% of the element's length and width. In particular, the light exit element differs from coatings and / or sheathing, especially opaque and / or reflective coatings, which are arranged on a side of the optical waveguide opposite the cooktop and / or along a circumference of the optical waveguide.

[0011] The term "intended" should be understood to mean, in particular, specially designed and / or equipped. The fact that an object is intended for a specific function should be understood to mean, in particular, that the object fulfills and / or performs this specific function in at least one application and / or operating state.

[0012] It is conceivable that the optical waveguide could be rod-shaped and / or cubic. To increase installation space efficiency and the size of the area of ​​the cooktop covered by the optical waveguide, it is proposed that the optical waveguide be plate-shaped. Preferably, the optical waveguide has at least one, preferably at least two, particularly opposite, sides with a flat, particularly smooth, surface. Preferably, the optical waveguide is free of concave outer surfaces. For example, the optical waveguide could be designed as an annular disk. Preferably, the optical waveguide is designed as a circular disk or a quadrilateral disk, particularly a rectangular disk. In particular, the optical waveguide covers a partial area of ​​the underside of the cooktop; alternatively, the optical waveguide could cover the entire underside of the cooktop.This allows, in particular, a simple and compact arrangement of the optical fiber below an area of ​​the cooktop to be illuminated.

[0013] Furthermore, it is proposed that the light-emitting element and the optical waveguide are formed, in particular, at least partially as a single piece, and that the light-emitting element has at least one coating on the base body. Alternatively or additionally, the light-emitting element could have at least one recess and / or raised area and / or roughened surface on the base body. In particular, the light-emitting element could be manufactured by at least one etching and / or cutting process performed on the base body. The phrase "formed, at least partially, as a single piece" means, in particular, that the light-emitting element and the optical waveguide share at least one common element, which is a component, and in particular a functionally important component, of both the light-emitting element and the optical waveguide.In particular, the coating of the base body serves exclusively to conduct the light. Advantageously, the light-emitting element additionally has at least one further coating on the base body, which differs from the coating, particularly with respect to one function. Alternatively, the light-emitting element can have only the further coating. In particular, the coating has at least one recess, which serves to define the light-emitting surface. Preferably, the further coating is arranged in the recess. This allows, in particular, for a further increase in installation space efficiency and simplifies the manufacture of the cooktop device. Advantageously, at least part of the light-emitting element can be manufactured simultaneously with the optical fiber.

[0014] It is conceivable that the cooktop device could have at least one separate diffuser element, which could, for example, be arranged between the light emission element and the cooktop surface and is designed to provide diffuse illumination of the cooktop surface. To further simplify the installation space efficiency and manufacturing of the cooktop device, it is proposed that the light emission element include at least one diffuser element. A "diffuser element" is understood to mean, in particular, an element designed to convert incident light into diffuse illumination.The term "diffuse illumination" is understood to mean, in particular, illumination whose radiant power is distributed, on average, homogeneously over a solid angle of at least π, preferably at least 3 / 2π, and particularly advantageously 2π, directly on a surface of the diffuser element facing the area to be illuminated, for a period of at least one hour. The diffuser element could be conical, rod-shaped, semi-tubular, or hemispherical. It could also be designed as a recess, a raised area, or a roughened surface of the light-emitting element or the base body. Finally, it could be designed as an adhesive element, for example, a silicone adhesive, which secures the optical fiber to the underside of the cooktop.Preferably, the diffuser element is designed in the form of a plate; particularly preferably, the diffuser element is designed as a coating. This eliminates the need for additional diffuser elements.

[0015] Furthermore, it is proposed that the light-emitting element defines a light barrier surface to prevent light from escaping the optical waveguide. A "light barrier surface" is understood to be, in particular, a surface that is opaque to light, at least in certain areas and / or at least for specific angles of incidence and / or at least for specific light frequencies, and preferably for light. It is conceivable that the light-emitting element and / or the base body has at least one recess and / or raised area and / or roughened surface that defines the light barrier surface. Preferably, the light-emitting element has at least one coating, more preferably the coating itself, that defines the light barrier surface. This allows the light-emitting surface to be defined in a particularly simple manner.

[0016] It is conceivable that the light barrier surface completely absorbs the light. To simplify the guidance of the light, it is proposed that the light-emitting element, in particular the light barrier surface, be at least partially reflective. The term "at least partially reflective" is understood to mean, in particular, that the light-emitting element is totally reflective at least in certain areas and / or at least for certain angles of incidence and / or at least for certain light frequencies, and preferably for all light frequencies. Advantageously, the coating of the optical waveguide is designed as a reflective coating. Particularly advantageously, the optical waveguide has at least one further reflective coating on the base body on a side of the optical waveguide facing away from the cooktop, which preferably extends over the entire side of the base body facing away from the cooktop.This allows, in particular, the light to be guided by total internal reflection on opposite sides of the optical waveguide.

[0017] It is possible for the light-emitting surface and the light-barrier surface to be arranged separately; for example, the light-emitting surface and the light-barrier surface could be separated by at least one opaque coating on the light-emitting element. To simplify the definition of the light-emitting surface, it is proposed that the light-emitting surface and the light-barrier surface together form a continuous surface on the side of the optical waveguide facing the cooktop. Advantageously, the continuous surface extends over the entire side of the optical waveguide facing the cooktop. Advantageously, the light-emitting surface is defined by recesses in the light-barrier surface. Particularly preferably, the diffuser element of the light-emitting element extends over the entire light-emitting surface.It is conceivable that the diffuser element is designed as the adhesive element and arranged in the recesses of the light barrier surface. Preferably, the diffuser element is designed as the additional coating and arranged in the recesses of the light barrier surface. This allows for the simple provision of diffuse lighting in predefined areas of the cooktop. Advantageously, a simple and space-saving design of the light emission surface and the light barrier surface can be achieved.

[0018] Furthermore, it is proposed that the side of the base body facing the cooktop be at least partially translucent. The term "at least partially translucent" is understood to mean, in particular, that the side of the base body facing the cooktop is at least partially transparent and / or at least for certain angles of incidence and / or at least for certain light frequencies, and preferably for light. Specifically, the optical waveguide has at least one reflective coating on both the side of the base body facing the cooktop and the side facing away from the cooktop. This eliminates the need for additional light-emitting elements to transmit light through the side of the base body facing the cooktop.

[0019] In a further aspect of the invention, it is proposed that the side of the base body facing the cooktop is at least partially reflective. In particular, the base body of the optical waveguide forms the entire optical waveguide. Specifically, the base body is totally reflective to light on both the side facing the cooktop and the side facing away from the cooktop. For example, the base body could have recesses and / or protrusions and / or roughened surfaces on both sides, which in particular extend completely across both sides. This allows for particularly simple manufacturing of the optical waveguide. Advantageously, reflective coatings of the optical waveguide can be omitted.

[0020] It is conceivable that the base body has at least one partial surface that is transparent to light. For example, this partial surface could be designed as a recess and / or raised area and / or roughened surface of the base body. To facilitate the simple definition of the light-emitting surface, it is proposed that the cooktop device has at least one contact element which, in a mounted state, contacts the side of the optical waveguide facing the cooktop, wherein the refractive index of the light-emitting element differs from that of the contact element. For example, the contact element could be made of air; in particular, the contact element could be the adhesive element or the cooktop itself.Preferably, in the assembled state, the side of the optical waveguide associated with the cooktop contacted the cooktop directly. Particularly preferably, the refractive index of the light-emitting element differs from that of the cooktop. In particular, the light-emitting element serves to eliminate total internal reflection of the light on the side of the base body facing the cooktop. Specifically, the light-emitting element is designed as an additional coating of the base body. Advantageously, the light-emitting element is designed as a diffusion element. This allows the light-emitting element to be produced by a simple coating of the base body. Advantageously, the light-emitting element can be printed onto the base body.

[0021] It is conceivable that the optical fiber unit could be attached to the underside of the cooktop by means of at least one snap connection, screw connection, plug connection, and / or locking connection. To facilitate easy attachment of the optical fiber unit, it is proposed that the unit be glued to the underside of the cooktop. Specifically, the optical fiber is glued to the underside of the cooktop by means of at least one adhesive element, which could, for example, be a silicone adhesive, an adhesive tape (especially double-sided tape), or other types of adhesive known to those skilled in the art. This allows the optical fiber unit to be easily attached to standard cooktops.

[0022] Finally, a cooktop, particularly an induction cooktop, with at least one cooking zone feature is proposed. This can significantly increase user comfort. The aesthetics of the lighting on a cooktop featuring this feature can be improved. New lighting designs and / or functions can be made particularly advantageous.

[0023] The cooktop device is not intended to be limited to the application and embodiment described above. In particular, the cooktop device may have a different number of individual elements, components, and units than specified herein to achieve the functionality described herein. Further advantages will become apparent from the following description of the drawings. The drawings illustrate two exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination.

[0024] They show: Fig. 1 A cooktop with a cooktop device in a top view, Fig. 2 the cooktop in a top view with an optical fiber unit of the cooktop device, Fig. 3 a sectional view of the cooktop along a section line AA from Fig. 2Fig. 4 shows a further embodiment of a cooktop with a cooktop device in a top view, and Fig. 5 shows a sectional view of the cooktop along a section line BB. Fig. 4 .

[0025] Of the objects that appear multiple times in the figures, only one is marked with a reference symbol.

[0026] Figure 1 Figure 3 shows a cooktop 32a. The cooktop 32a is designed as an induction cooktop. The cooktop 32a has a cooking zone 36a. The cooking zone 36a is located in the center of the cooktop 32a. The cooktop 32a has a cooktop device 10a, which is located in Figure 2 The hob device 10a serves to illuminate the cooking zone 36a. Alternatively or additionally, the hob 32a could have further hob devices, which could in particular serve to illuminate further cooking zones of the hob 32a.

[0027] The cooktop device 10a includes a cooktop plate 12a. The cooktop plate 12a is made of glass-ceramic. Alternatively, the cooktop plate 12a could be made of other common materials known to those skilled in the art for cooktops. The cooktop device 10a includes a fiber optic unit 16a, which is located in Figure 3This is shown in more detail in a sectional view. The optical fiber unit 16a is arranged on the underside 14a of the cooktop panel 12a. The optical fiber unit 16a is adhered to the underside 14a of the cooktop panel 12a. The optical fiber unit 16a is adhered to the underside 14a of the cooktop panel 12a by means of an adhesive element (not shown). The adhesive element is a silicone adhesive. Alternatively, the adhesive element could be a double-sided adhesive tape or other adhesive elements known to those skilled in the art. The optical fiber unit 16a has an optical fiber 18a. Alternatively or additionally, the optical fiber unit 16a could have further optical fibers. The optical fiber 18a serves to transmit light.

[0028] The cooktop device 10a includes a light source unit 38a. The light source unit 38a has four light sources 40a. The light sources 40a are provided for the provision of light. The light sources 40a are arranged on four pairs opposite sides of the optical waveguide 18a. The light sources 40a are arranged on sides of the optical waveguide 18a that are oriented perpendicular to the cooktop surface 12a. Alternatively or additionally, the light source unit 38a could have any other number of light sources 40a and arrangement of the light sources 40a. The light sources 40a provide light. Each light source 40a defines a direction of light radiation. The directions of radiation are directed towards the optical waveguide 18a. For the sake of clarity, the expression "the light provided by the light sources 40a" will be abbreviated to "the light" in the following.

[0029] The optical waveguide 18a is plate-shaped. The optical waveguide 18a is disk-shaped. The optical waveguide 18a has a base body 34a. One side of the base body 34a facing the cooktop 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 located on one side of the optical waveguide 18a facing away from the cooktop 12a. The first reflective coating 42a extends over the entire side of the optical waveguide 18a facing away from the cooktop 12a. The first reflective coating 42a serves to guide the light within the optical waveguide 18a.

[0030] 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 located on the side of the optical waveguide 18a facing the cooktop 12a. The second reflective coating 26a has recesses 44a. The second reflective coating 26a serves to guide the light within the optical waveguide 18a.

[0031] The cooktop device 10a has a light emission element 20a. The light emission element 20a defines a light emission surface for the exit of light from the optical fiber 18a. The light emission element 20a is arranged on the side of the optical fiber 18a facing the cooktop surface 12a. The light emission element 20a is partially integral with the optical fiber 18a. The light emission element 20a is partially reflective. The light emission element 20a and the optical fiber 18a jointly have the second reflective coating 26a. The second reflective coating 26a serves to define the light emission surface. The second reflective coating 26a defines a light barrier surface to prevent light from exiting the optical fiber 18a. The recesses 44a of the second reflective coating 26a define the light emission surface.

[0032] The light-emitting surface and the light-barrier surface together form a continuous surface 30a on the side of the optical waveguide 18a facing the cooktop 12a. The continuous surface 30a extends over the entire side of the optical waveguide 18a facing the cooktop 12a.

[0033] The light emission 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 serves to provide diffuse illumination of the cooktop surface 12a.

[0034] In Figures 4 and 5Another embodiment of the invention is shown. The following descriptions are essentially limited to the differences between the embodiments, whereby with regard to components, features and functions that remain the same, reference is made to the description of the embodiment of the Figures 1 to 3 Reference can be made to. To distinguish the embodiments, the letter a in the reference numerals of the embodiment is used in the Figures 1 to 3 by the letter b in the reference numerals of the embodiment of the Figures 4 and 5 replaced. With regard to identically designated components, especially those with the same reference numerals, reference can generally also be made to the drawings and / or the description of the embodiment of the Figures 1 to 3 be referred.

[0035] The Figures 4 and 5Figure 1 shows a further embodiment of a cooktop 32b with a cooktop device 10b. The cooktop device 10b has a cooktop plate 12b. The cooktop 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 horizontally spaced from the cooktop plate 12b.

[0036] The cooktop device 10b comprises an optical fiber unit 16b. The optical fiber unit 16b comprises an optical fiber 18b. The optical fiber 18b is designed as a rectangular disk. The optical fiber 18b extends over the entire underside 14b of the cooktop surface 12b. The optical fiber 18b has a base body 34b. One side of the base body 34b facing the cooktop surface 12b is totally reflective. One side of the base body 34b facing away from the cooktop surface 12b is totally reflective.

[0037] 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 cooktop 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 oriented perpendicular to the cooktop 12b.

[0038] The cooktop device 10b has a light emission element 20b. The light emission element 20b has a light-extracting coating 22b of the base body 34b. The light-extracting coating 22b completely forms the light emission element 20b. The light-extracting coating 22b is designed as a diffuser element 28b.

[0039] The cooktop device 10b has a contact element 24b. The contact element 24b contacts the side of the optical waveguide 18b facing the cooktop plate 12b. The contact element 24b is made of air. The light-extracting coating 22b has a refractive index that differs from that of air. Alternatively, the contact element 24b could be designed as an adhesive element or as the cooktop plate 12b itself. The light-extracting coating 22b serves to prevent total internal reflection of the light on the side of the base body 34b facing the cooktop plate 12b. Reference sign

[0040] 10 Cooktop device 12 Cooktop plate 14 Underside 16 Optical fiber unit 18 Optical fiber 20 Light emission element 22 Light-extracting coating 24 Contact element 26 Second reflective coating 28 Diffuser element 30 Continuous surface 32 Cooktop 34 Base body 36 Cooking zone 38 Light source unit 40 Light source 42 First reflective coating 44 Recess

Claims

1. Hob device (10a-b), in particular induction hob device, having at least one hob plate (12a-b), having a heating element, having at least one optical waveguide unit (16a-b) which is arranged on an underside (14a-b) of the hob plate (12a-b) and has at least one optical waveguide (18a-b) for guiding light, which has a base body (34a-b) and at least one light exit element (20a-b), which is provided to define a light exit surface for an exit of the light from the optical waveguide (18a-b), wherein the light exit element (20a-b) is arranged on a side of the optical waveguide (18a-b) facing the hob plate (12a-b), and wherein the optical waveguide (18a-b) is plate-shaped and in at least one operating state transmits electromagnetic radiation along a main extension plane of the optical waveguide (18a-b), characterised in that the optical waveguide (18a-b) is arranged in an assembled state between the hob plate (12a-b) and the heating element.

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

3. Hob device (10a-b) according to one of the preceding claims, characterised in that the light exit element (20a-b) has at least one diffusor element (28a-b).

4. Hob device (10a-b) according to one of the preceding claims, characterised in that the light exit element (20a) defines a light barrier surface to prevent light from escaping from the optical waveguide (18a).

5. Hob device (10a) according to claim 4, characterised in that the light exit element (20a) is at least partially reflective.

6. Hob device (10a) according to claim 4 or 5, characterised in that the light exit surface and the light barrier surface together form a cohesive surface (30a) of the side of the optical waveguide (18a) facing the hob plate (12a).

7. Hob device (10a) according to one of the preceding claims, characterised in that a side of the base body (34a) facing the hob plate (12a) is at least partially light-permeable.

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

9. Hob device (10b) according to claim 8, characterised 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), wherein an index of refraction of the light exit element (20b) differs from an index of refraction of the contact element (24b).

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

11. Hob (32a-b) having at least one hob device (10a-b) according to one of the preceding claims.

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