Sensor element device, operating device, and electrical equipment having the same

Abstract

A sensor element arrangement for an operating device with an illuminated display comprises: a sensor element for a capacitive touch switch; a light guide for the illuminated display, the light guide having an input area and an emission area; and a light-impermeable shielding material surrounding the light guide except for the input area and the emission area. The arrangement also includes a bottom side and an upper side, and at least one metal sensor element. The sensor element extends from the bottom side to the upper side. The sensor element arrangement forms an integrated module with the light guide, the shielding material, and the sensor element. The sensor element protrudes beyond the plane of the bottom side. No portion of the sensor element arrangement protrudes downward.

Description

Technical Field

[0001] The present invention relates to a sensor element arrangement for an operating device having an illuminated display and a capacitive touch switch, an operating device having at least one such sensor element arrangement, and an electrical appliance having such an operating device. Background Art

[0002] US Pat. No. 5,917,165 A1 discloses a capacitive touch switch for electric cooktops, which utilizes a capacitive sensor element in its associated operating mechanism. The cooktop serves as the operating surface. A conductive elastic body is pressed against the underside of the cooktop at the operating surface. The conductive upper side of the body forms the capacitive sensor element for the capacitive touch switch. Internally, the body includes a continuous light-conducting channel in which LEDs are arranged as illumination devices. Light from the LEDs shines through the cooktop from below, generating a light-emitting display.

[0003] DE 10 2015 214 008 A1 discloses another sensor element arrangement that can be integrated into a cooktop and provides both an illuminated display and a capacitive touch switch. In this arrangement, a light-impermeable shielding material is injection-molded around a light guide body, both of which are electrically insulating. Stamped and repeatedly bent metal parts form the capacitive sensor element and are arranged on the upper side and downwardly on two opposing outer sides. On the lower side, two elongated pins protrude downwardly from the shielding material beyond the lower side. The sensor element arrangement can thus be fastened to a printed circuit board using LEDs as lighting devices. Summary of the Invention

[0004] Purpose and Solution

[0005] The object of the present invention is to provide a sensor element arrangement as mentioned in the introduction, an operating device and an electrical device provided with such an operating device, by means of which the problems of the prior art can be solved and in particular the sensor element arrangement can be constructed simply and conveniently and in particular can be mounted simply and reliably so as to advantageously manufacture the operating device.

[0006] This object is achieved by a sensor element arrangement having the features of claim 1, an operating device having the features of claim 15, and an electrical device having the features of claim 17. Advantageous and preferred embodiments of the invention are the subject of the further claims and are explained in more detail below. In this context, many features are described with respect to only the sensor element arrangement, only the operating device, or only the electrical device. Regardless, it is intended that they can be applied individually and independently of one another to the sensor element arrangement, the operating device, and the electrical device. The wording of the claims is incorporated into the description by explicit reference.

[0007] The sensor element arrangement includes at least one sensor element to form a capacitive touch switch, which is then present on an operating device provided with the sensor element arrangement. The sensor element arrangement also includes a light guide, which forms a light-emitting display. The light guide is composed of a light-transmitting material that is transparent, translucent, or opaque to form a more uniform light pattern. The light guide includes an input area for light and an emission area for light. The sensor element arrangement also includes a shielding material that surrounds the light guide, leaving substantially only the input area and the emission area uncovered. The shielding material is constructed or selected such that it is light-impermeable or light-transmitting, either because it is completely light-impermeable or because, in conjunction with the light guide, particularly at a connection surface, it transmits no light or reflects all light back into the light guide. The sensor element arrangement includes a bottom side and a top side, particularly when it has a rectangular parallelepiped shape or is configured as a rectangular parallelepiped or block-shaped. In this case, the bottom side and the top side are disposed opposite each other on the rectangular parallelepiped or block-shaped surface. The emission region of the light guide is advantageously arranged close to or on the upper side. The input region is advantageously arranged below the upper side, or a recess is provided below the sensor element arrangement, in which recess an illumination device (e.g., an LED) can be accommodated, so that at least a minimum distance from the input region is provided above the input region.

[0008] The sensor element arrangement further comprises at least one metal sensor element as a component, which is composed of at least one metal part. Advantageously, the sensor element arrangement comprises one or two metal parts, which together form a capacitive sensor element for a single touch switch of the sensor element arrangement. For this purpose, they can advantageously be electrically connected. The sensor element extends from the bottom side to the top side and advantageously forms a plane of the bottom side and the top side or extends within these planes.

[0009] The sensor element arrangement forms an integrated module with the light guide, the shielding material and the sensor element. It can advantageously be produced as an injection-moulded part, which allows for economical and precise production.

[0010] In this case, the sensor element or the metal part projects as far as the plane of the underside of the sensor element arrangement so that it at least partially defines this plane or extends therein. The same structure can also be provided on the upper side, although this is not necessary.

[0011] According to the present invention, no part of the sensor element device protrudes downward beyond the lower side of the sensor element device or the sensor element itself, or does not protrude downward. This ensures that when the sensor element device is placed on a flat surface with a sensor element, the sensor element device contacts the flat surface or protrudes at most 1 mm. Therefore, with the present invention, the sensor element device can be electrically connected well, simply and reliably in the long term. This electrical connection can also be mechanically fastened. In particular, the electrical connection can preferably be constructed as an SMD connection so that it can be produced very advantageously. In this case, it is also possible to achieve the effect that the sensor element device and advantageously a plurality of sensor element devices of equal or identical design can be placed on a component carrier of an operating device in a known manner by an SMD assembly machine.

[0012] In an advantageous embodiment of the invention, the sensor element does not adjoin the light guide or its light-transmitting material. It is considered advantageous if the sensor element extends at a distance from the light guide, i.e., with a spacing of at least 1 mm, so that the corresponding construction can be optimized as much as possible for its function. This applies both to the light guide or its shape formed from the light-transmitting material, and to the sensor element. This is significantly easier for the shielding material, since it has the sole purpose of being light-proof or of not allowing light to escape undesirably from the light guide. The shielding material therefore advantageously extends at least partially between the light guide and the sensor element, or there is always shielding material between the light guide and the sensor element.

[0013] In a further embodiment of the invention, the sensor element or individual sensor elements can extend on one side of the sensor element arrangement. In particular, it can extend on the outer side so that this side substantially adjoins the air or faces outwards.

[0014] In an alternative embodiment of the invention, in particular when a plurality of sensor elements are provided on a single sensor element arrangement, it may be preferred that at least one sensor element extends on at least two sides of the sensor element arrangement. If only a single sensor element is provided on the sensor element arrangement, these are advantageously two mutually adjacent sides, three mutually adjacent sides or even all mutually adjacent sides. As an alternative, at least two sensor elements spaced a certain distance apart from each other may be provided on a single sensor element arrangement, said sensor elements then advantageously being provided on opposite sides. This applies in particular to a cuboid or block-like shape of the sensor element arrangement, respectively. If two sensor elements spaced a certain distance apart from each other are provided for manufacturing and inventory reasons, it is preferred that they are mirror-symmetrically identical or even identical. In this case, it may also be advantageous to provide that all sensor elements on the sensor element arrangement are electrically interconnected with each other or function as a single capacitive sensor element by connection in order to form a capacitive touch switch.

[0015] Such integrally attached sensor elements or the metal parts forming them are advantageously repeatedly bent or angled so that they can be adapted to the shape of the sensor element arrangement and, in particular, can also be configured for electrical contacting.

[0016] In one advantageous embodiment of the present invention, the sensor element arrangement is produced by injection molding, particularly by a multi-component injection molding method. In this case, the light guide and the shielding material are advantageously injection molded onto one another, in a variable order. The at least one metal sensor element can then be fastened to this component to form the sensor element arrangement. Alternatively, the shielding material can also be injection molded around the at least one sensor element, particularly together with the light guide. In this case, the at least one sensor element can be injection molded onto the sensor element arrangement or at least partially around it, ensuring a stable and permanent connection to the sensor element arrangement. However, in particular, the sensor element is not injection molded around the underside of the sensor element arrangement, or is exposed on the underside of the sensor element arrangement, advantageously having a height exceeding the underside by up to 2 mm or up to 3 mm. This allows for the aforementioned electrical and mechanical connections, preferably by means of SMD soldering. The sensor element should also be exposed on the top side so that it can be pressed directly onto the underside of the operating surface of the operating device according to the present invention. Alternatively, a thin covering, for example, made of the shielding material or, alternatively, of elastic silicone, can be provided above it.

[0017] The sensor element can be bent in the region of the upper side and / or the lower side so that it bends toward the center region of that side, i.e., not away from the sensor element arrangement or the light guide (which advantageously extends approximately through the center of the sensor element arrangement or the light guide), but rather toward them. In this case, the bend can be implemented approximately at a right angle, so that the curved section of the sensor element extends approximately parallel to, and advantageously along, the upper or lower side or, respectively, along their plane. Provision can also be made for these curved sections of the sensor element to maintain a spacing from the light guide.

[0018] In addition to or as an alternative to the aforementioned covering over the sensor element arrangement, which can be composed, for example, of elastic silicone, a light-impermeable covering or coating can be provided over the entire upper side of the sensor element arrangement, or only on the upper side of the light guide (i.e., advantageously in the emission region). Advantageously, it is designed so that it can be removed in desired areas to enable the display of transmissively illuminated symbols or logos, as is known from the prior art for such sensor element arrangements, see, for example, the aforementioned DE 10 2015 214 008 A1. This light-impermeable covering or coating can be relatively thin; it only needs to be light-impermeable, particularly for the luminous intensity of LEDs, such as those conventionally used in operating devices for electrical appliances. A particularly advantageous option is to use a laser to remove the light-impermeable covering or coating to create a segment for transmitting light from the emission region. This makes it possible to provide not only arbitrary or general illuminated displays, but also displays in the form of symbols.

[0019] In an advantageous embodiment of the invention, provision is made that precisely one sensor element arrangement forms precisely one capacitive touch switch. In a similar manner, it also forms precisely one single illuminated display.

[0020] The sensor element can consist of a relatively thin metal, for example a copper sheet with a thickness of 0.01 mm to 0.5 mm. On the top side, the sensor element can be bent by a length of 0.5 mm to 2 mm to provide a specific area that, although small, is generally very advantageous for reliable function as a capacitive touch switch.

[0021] The operating device according to the present invention advantageously includes a component carrier, in particular a printed circuit board, on which the sensor element arrangement is arranged and electrically connected. Advantageously, all sensor element arrangements of the entire operating device are arranged and electrically connected on this component carrier. To this end, at least one contact area can be provided on the top side, advantageously one contact area for each individual sensor element part of the sensor element arrangement. The sensor element arrangement can be electrically connected and fastened thereto, advantageously by means of the aforementioned SMD soldering, or alternatively by means of a conductive adhesive.

[0022] In addition to the electrical appliance according to the invention, which can be designed as an electric cooktop or hob, a cooktop panel whose one part forms the operating surface, other electrical appliances, in particular electric cooking appliances, can be provided with such an operating device according to the invention. These electrical appliances can be ovens, microwave ovens or steam cookers, but can also be other electrical appliances such as dishwashers or washing machines.

[0023] These and other features are disclosed in the claims as well as in the description and drawings; in embodiments of the invention as well as in other fields, individual features can be implemented individually or in combination and in subcombinations and can represent advantageous and per se protectable embodiments of the invention claimed herein. The subdivision of the application into individual sections and subheadings does not limit the general applicability of the statements made therein. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Exemplary embodiments of the present invention are schematically represented in the accompanying drawings and will be explained in more detail below. In the drawings:

[0025] Figure 1 shows a cross-sectional representation through a sensor element arrangement according to the invention in a first configuration of the invention,

[0026] Figure 2 Shown Figure 1 Plan view of the sensor element arrangement,

[0027] Figure 3 shows a side view of an operating device according to the invention with the aforementioned sensor element arrangement integrated in the cooktop, and

[0028] Figure 4 A cross-sectional view similar to Figure 1 A variant of the operating device of the operating device. DETAILED DESCRIPTION

[0029] Figure 1The sensor element arrangement 11 according to the invention is shown in a side view or lateral section. The sensor element arrangement 11 comprises an upper side 12 and an underside 13, each of which is represented here by dots and a dashed line. The upper side 12 and the underside 13 extend substantially in a plane.

[0030] The sensor element arrangement 11 is produced as an integrated component and comprises a sensor element 15a on the left and a sensor element 15b on the right. The sensor element 15a comprises an upper angle section 16a and a lower angle section 17a. A side portion 18a extends between them. The right sensor element 15b is identically constructed with an upper angle section 16b, a lower angle section 17b and a side portion 18b therebetween. The right sensor element 15b is arranged mirror-symmetrically with respect to the left sensor element 15a. The angle sections 16 and 17 are each approximately at right angles to the side portion 18 and can in fact also be constructed to be more rounded. As can be seen, the upper and lower sides of the upper angle section 16 each extend precisely in the plane of the upper side 12. In a similar manner, the upper and lower sides of the lower angle section 17 extend precisely in the plane of the lower side 13. While the angular sections 16 and 17 are constructed so to speak two-dimensionally and without interruptions or breaks, the situation may be different for the side portions 18, in particular in order to facilitate the injection molding process or injection. This will be discussed in more detail below.

[0031] In the central region of the sensor element arrangement 11, a light guide 20 made of a light-transmitting material is arranged. This light guide can advantageously be completely transparent or slightly opaque. Due to this opaque design, the transmitted illumination and thus the resulting luminous display can be made more uniform, even if the luminous intensity is reduced. The light guide 20 comprises an input region 22 at the bottom and an emission region 23 at the top. It is surrounded by a light-impermeable shielding material 26, which is in particular provided by a Figure 2 1 is shown in a plan view of the sensor element arrangement 11 in FIG. The material completely surrounds the light guide 20 on all four sides and may extend as far as the plane of the lower side 13. Below the light guide 20 or the input area 22, a recess 28 is thus formed, in which an LED 30 indicated by a dashed line can be arranged for illuminating the display.

[0032] Shielding material 26 and light guide 20 are advantageously produced together via injection molding. Advantageously, shielding material 26 can be injection molded around light guide 20, which is already a finished part. Sensor elements 15a and 15b can then be laterally applied or secured, for example, by latching, clamping, or clipping. In another configuration, light guide 20 and sensor elements 15a and 15b can be introduced into an injection mold and then injection molded around them along with shielding material 26 to form the component. Shielding material 26 and light guide 20 are advantageously electrically insulating.

[0033] from Figure 1 As can be seen in FIG, the top sides of emission region 23 and shielding material 26 also do not protrude beyond the plane of top side 12 or extend therein. Similarly, shielding material 26 extends on its underside in the plane of underside 13 of the entire sensor element arrangement 11. Due to recess 28, input region 22 of light guide 20 is significantly higher here.

[0034] Figure 2 The plan view of the sensor element arrangement 11 in FIG. 1 reveals how the sensor elements 15 a and 15 b form a specific area with the upper angled sections 16 a and 16 b or two separate areas, which are electrically connected together in the operating device. Even though their area appears small, it is still sufficient to form a sufficient area for the capacitive sensor element formed thereby to be used in a capacitive touch switch. However, this is known per se to those skilled in the art. Since the sensor element arrangement has an advantageous length of between 5 mm and 15 mm and a width of between 3 mm and 9 mm, the two upper angled sections 16 a and 16 b, and therefore the two sensor elements, are generally covered when a finger is placed on the contact surface.

[0035] In the plan view, the light guide 20 is indicated by a dotted line. It is covered at the top by a thin, light-impermeable coating 32. The coating 32 may also cover the entire upper side of the shielding material 26 and possibly also the upper side of the upper angular segment 16. This coating 32 is constructed in such a way that a symbol segment 34 can be cut out by laser in a manner known per se, here into an "H," for example, for a thermal display. Therefore, no coating is provided in this symbol segment 34, allowing light to exit the light guide 20 at the emission region 23. This provides a light-emitting display 36 having a luminous or illuminated "H."

[0036] It is also easily conceivable to provide a sensor element on only one of the two sensor elements shown in each case, i.e. only on one side. Likewise, the sensor element can also be bent, so to speak, once or twice around a corner on the outside of the sensor element arrangement 11, said corner pointing into or out of the plane of the drawing. Figure 1 and 2 It can also be seen in FIG. 1 that the entire sensor element arrangement 11 has a rectangular parallelepiped or block-like shape.

[0037] The coating 32 on the upper side 12 of the sensor element arrangement 11 should advantageously not be too thick. It can optionally be calculated in terms of thickness so that it is at the same height on the upper side of the light guide 20 and the shielding material 26 as on the upper side of the upper angled section 16. Alternatively, it can also overlap these or extend over them in order to serve as a type of scratch protection, so that the metal sensor element 15 does not bear against and scratch the underside of the cooktop plate 48, which is typically made of glass ceramic.

[0038] Figure 3 Shown Figure 1 and 2 The sensor element assembly 11 is integrated into the operating device 40. The operating device 40 includes a printed circuit board 41 having two contact areas 42a and 42b spaced apart from each other. Conductive tracks for electrical connection are not shown. The sensor element assembly 11 is supported on these contact areas 42 and soldered to a small portion of the lower area of ​​the lower angled sections 17a and 17b and the side sections 18a and 18b using solder 44a and 44b. This is advantageously implemented in an SMD process by placing the sensor element assembly 11 onto a prepared printed circuit board 41 using an SMD assembly machine. A small amount of solder 44a and 44b is then already present on the contact areas 42a and 42b. Furthermore, conventional SMD adhesives for mechanical fastening can mechanically secure the sensor element assembly 11 after placement or assembly, until it is not only electrically connected but also permanently mechanically secured using solder 44a and 44b. In a similar manner, the LED 30 is fastened as an SMD component to contact areas (not shown) on a printed circuit board 41 .

[0039] The operating device 40 comprises an operating surface located at the top. For this purpose, a cooktop 48 is used, into which the cooktop 46 of the operating device 40 is integrated. The cooktop 48 comprises a lower side 49 and an upper side 50. A touch surface 51 is formed on the upper side 50 of the sensor element device 11, which is where the capacitive touch switch can be actuated, so to speak, by placing the finger of the person operating it. The cooktop 48 is also light-transmissive, so that the light from the LED 30 can shine through, and optionally, it is advantageously formed with a similar Figure 2 A specific luminous display 36 in the shape of a symbol is provided. This is also known from similar sensor element arrangements.

[0040] Advantageously, although the cooktop 46 comprises only a single operating device 40, it nevertheless has a plurality or a large number of sensor element devices 11, for example between five and fifty, on its printed circuit board 41. All sensor element devices 11 are placed with their upper sides on the lower side 49 of the cooktop 48, so that a precise and consistent allocation of the upper angle segments 16 to the cooktop 48 and the upper side 50 is achieved.

[0041] Figure 4 Figure 1 shows a further variant of the sensor element arrangement 111 according to the invention. Figure 1 , which comprises a light guide 120 and a shielding material 126 surrounding the light guide. A recess 128 for the LED is provided at the bottom. On the left side a first configuration of an alternative sensor element 115a is provided, which has a corresponding Figure 1 The upper angled section 116a and side sections 118a are curved. However, the lower angled section 117a curves outward rather than inward. This may facilitate fastening or electrical contact. It is also readily apparent that, regardless of the configuration of the lower angled section 117a, the upper angled section 116a may similarly curve outward, i.e., away from the sensor element arrangement 111.

[0042] The right sensor element 115b is again designed differently. Here, only the side portion 118b is actually provided, with no angled sections at the top or bottom. Therefore, the sensor element or side portion can be generally flat, in particular, without protruding or curved sections or portions. At the bottom, a lower edge 117b' of the side portion 118b is provided, sufficient for electrical contacting via SMD soldering. This can overlap laterally on the outside of the side portion 118b in the lower region. At the top, only the side edge 116b' of the side portion 118b is provided, so that the area for the capacitive sensor element here is essentially formed or composed solely of the area of ​​this side edge. Due to the material thickness of the side portion 118b, this results in a very small area for the capacitive sensor element. Consequently, the resulting capacitive touch switch may not be very sensitive, or more precisely, prone to errors. However, this can be effectively compensated for with appropriate connections, control, and evaluation. Such sensor elements 115 b can naturally be manufactured very easily, since they do not have any angled sections, and they can also be used relatively easily in an injection molding method for producing the sensor element arrangement 111 .

[0043] from Figure 1 and Figure 4 It can be seen that no part of the sensor element arrangement protrudes beyond the plane of the upper side or the plane of the lower side, respectively. However, the sensor element arrangement can be fastened well and reliably to the component carrier or printed circuit board 41 by means of SMD soldering.

Claims

1. A sensor element arrangement for an operating device having an illuminated display, wherein: The sensor element device comprises a sensor element for a capacitive touch switch of the operating device, comprising: a light guide for said light-emitting display, said light guide consisting of a light-transmitting material, said light guide comprising an input area for light and an emission area for light, a shielding material surrounding the light guide except for the input area and the emission area, the shielding material being light-tight in combination with the light guide, - at least one metallic sensor element consisting of at least one metallic part, in: - the sensor element arrangement comprises a lower side and an upper side, - the sensor element extends from the lower side of the sensor element arrangement to the upper side of the sensor element arrangement, - the sensor element arrangement forms an integrated module with the light guide, shielding material and sensor element, the sensor element protrudes as far as the plane of the underside of the sensor element arrangement and at least partially defines the plane of the underside, - No part of the sensor element arrangement protrudes downwards beyond the underside of the sensor element arrangement or beyond the sensor element.

2. The sensor element device according to claim 1, wherein The sensor element does not adjoin the light guide or extends at a distance from the light guide.

3. The sensor element device according to claim 1, wherein The sensor element extends on one side of the sensor element arrangement.

4. The sensor element device according to claim 1, wherein The sensor element extends on at least two sides of the sensor element arrangement.

5. The sensor element device according to claim 4, wherein: The sensor element extends on at least two sides of the sensor element arrangement in one of the following configurations: (1) On mutually adjacent sides, wherein bent or angled individual sensor elements are provided; or (2) Extending on opposite sides, wherein two sensor elements are provided at a distance and separated from each other.

6. The sensor element device according to claim 1, wherein The sensor element arrangement is produced by a multi-component injection molding method, the sensor element being injection molded onto or into the sensor element arrangement or at least partially around the sensor element arrangement.

7. The sensor element device according to claim 1, wherein The sensor element is arranged on the outer side and is exposed on the outer side.

8. The sensor element device according to claim 1, wherein The sensor element is bent onto the underside in the region of the underside of the sensor element arrangement.

9. The sensor element device according to claim 1, wherein The sensor element is bent in an upper region toward a central region of the top side, the upper region extending in the surface of the top side of the sensor element arrangement.

10. The sensor element device according to claim 9, wherein The sensor element is bent approximately at a right angle and is spaced apart from the light guide.

11. The sensor element device according to claim 10, wherein: A light-impermeable covering or coating is provided on the upper side of the sensor element arrangement or the light guide.

12. The sensor element device according to claim 11, wherein The light-impermeable cover or coating is configured in such a way that it can be removed by laser in order to carve out segments for transmitting light from the emission area of ​​the light guide for use in a light-emitting display.

13. The sensor element device according to claim 1, wherein Precisely one sensor element arrangement forms precisely one capacitive touch switch.

14. An operating device comprising a capacitive touch switch and the sensor element device according to claim 1 for the capacitive touch switch, wherein: The operating device comprises an operating surface, below which the sensor element arrangement is arranged, and on the underside of which the sensor element or one of the sections of the sensor element is supported.

15. The operating device according to claim 14, wherein: A component carrier is provided, on which the sensor element arrangement is arranged and electrically connected, and which comprises on its top side at least one contact area, on which the sensor element is supported and mechanically and electrically connected.

16. An electrical device having an operating device according to claim 14, wherein: The electrical appliance is an electric cooktop having a cooktop, a portion of which forms an operating surface, the operating device being arranged below the cooktop and comprising a multiplicity of sensor element arrangements.

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