Sensor device or module for determining displacement or deflection or bending, household appliance and method for determining the weight of an item

Abstract

The invention relates to a sensor device (11, 35, 49, 71) or module for determining a, in particular elastic, displacement or deflection or bending of a panel (3), in particular a glass panel, or of a section of the panel, or of an insert relative to the panel (3). The sensor device (11, 35, 49, 71) or module and the panel (3) or the section of the panel form a weighing device, in particular a scale. The sensor device (11, 35, 49, 71) or module is adapted to be integrated in or assigned to a household appliance (1), in particular a cooking hob, more particularly an induction cooking hob, and comprises or is connected to at least one processing and / or interpretation and / or evaluation device for providing, in particular, a high sensor sensitivity and / or an estimation unit accuracy. Further, a household appliance (1) is disclosed, which comprises an at least substantially horizontal panel (3), in particular a glass panel. The panel (3) is part of or functionally connected to a scale for weighing an item (15) placed on the panel (3). Finally, the invention relates to a method for determining a weight of an item (15) located on an at least substantially horizontal panel (3) of a household appliance (1), in particular a top panel (3) of a cooking hob. An acceleration of a panel section or a panel reference point or a panel reference area, in particular a reference point or a reference area located on a panel surface (7), is estimated or determined during a displacement or deflection or bending of the panel section or the panel reference point or panel reference area due to placing an item (15) on the panel.

Description

[0001] The present invention relates to a sensor device or module for determining a displacement or deflection or bending, in particular an elastic displacement or deflection or bending, of a panel or of a section thereof or of an insert relative to the panel. The present invention further relates to a household appliance, in particular a cooking hob, more particularly an induction cooking hob, comprising an at least substantially horizontal panel. Finally, the present invention relates to a method for determining a weight of an item located on an at least substantially horizontal panel of a household appliance, in particular a top plate of a cooking hob.

[0002] In order to correctly handle items in a household, it can be beneficial to know the weight of the items. For example, if a user knows the actual load of laundry put in, an overload of the oscillation system in a washing machine can be avoided. Further, the dosage of detergent can be adjusted according to the laundry load. In the field of food preparation, a weighing unit or device integrated in a cooking hob or oven or distributed to a cooking hob or oven can help the user to precisely add a certain amount of ingredients to the food even after the cooking process has started or during the preparation process to prepare the food for cooking and does not require an additional kitchen scale that occupies space on the kitchen worktop.

[0003] From DE 199 26 513 A1 a cooking hob with a scale unit is known. The cooking hob comprises a glass top plate and a detection unit that recognizes a deformation of the top plate due to a weight load of a cooking vessel and determines the associated weight. The detection unit comprises a bending lever and a dedicated strain gauge that is connected to processing circuitry for interpreting the signal of the strain gauge.

[0004] It is an object of the present invention to provide a sensor device or module, a household appliance and / or a method for determining a weight of an item, such that the determination of the weight of the item is further improved by means of a measurement technology that relies on a displacement or deflection or bending of a panel.

[0005] This object is achieved by a sensor device or module according to the present invention for determining a displacement or deflection or bending of a panel or of a section of the panel or of an insert relative to the panel.

[0006] According to a first aspect of the present application, a sensor device or module for determining a displacement or deflection or bending of a panel, in particular a glass panel or a glass-ceramic panel, or of a section of the panel, or of an insert relative to the panel is provided. The displacement or deflection or bending, in particular an elastic displacement or deflection or bending, can be any kind of misalignment of the entire panel relative to its original or regular position or alignment, in particular its planar alignment, or of only one section of the panel relative to one or more other sections which remain unaffected. It can also include a misalignment of an insert portion or insert component relative to the panel, in particular to an unaffected panel. The expression "determining a displacement or deflection or bending" can be understood as a mere detection of the presence of such a misalignment or an estimation or an exact measurement of its value or level. The sensor device or module and the panel or the section of the panel form a weighing device, in particular a weighing scale. The sensor device or module is adapted to be integrated in or assigned to a household appliance, and comprises or is connected to at least one processing and / or interpreting and / or compiling device, which can provide a particularly high sensor sensitivity and / or estimation unit accuracy. The household appliance can be a cooking hob, in particular an induction cooking hob, and the panel, in particular the glass panel, can be a top plate comprising at least one cooking zone.

[0007] The sensor device or module can be or can comprise a light sensor for measuring a distance from a surface of the panel. A reference point or reference area can be defined on the panel for making the distance measurement. The light sensor is preferably positioned below the panel. Furthermore, the light sensor can be a light interrupter. With this type of sensor, particularly small surface movements of about 0.01 to 0.3 mm occurring in the case of a glass displacement or deflection or bending are detectable and measurable. Light interrupters generally show a high resolution within a distance of 0 and 0.5 mm.

[0008] According to a specific embodiment, the light sensor is a reflective light sensor and the reference point or reference area for making the distance measurement comprises a reflective surface. The reflective surface is preferably a shiny surface, in particular a shiny metal surface, of the panel. The reflective surface can also be a printed glass surface, in particular a glass surface with a metal evaporation. Finally, the reflective surface can be a color droplet, in particular a white droplet, or a printed surface applied on a surface of the panel, in particular facing the light sensor.

[0009] The sensor device or module, in particular the light sensor, can be arranged or can be able to be arranged away from the panel, which arrangement can facilitate an accurate distance measurement. The advantageous arrangement is performed at a housing or frame portion of the household appliance or of a component or module arranged inside the household appliance. In a preferred embodiment, the light sensor is applied on a printed circuit board, which is in particular connected or fixed to the housing or to the frame portion.

[0010] In addition to or as an alternative to the above-described embodiments comprising light sensors, an acceleration sensor can be provided for detecting an acceleration of the panel segment or the panel reference point or panel reference area during an elastic displacement or deflection or bending of the panel segment or the panel reference point or panel reference area in particular as a result of the placement of an item to be weighed on the panel. The reference point or reference area can be located on the panel surface. The acceleration sensor can be at least adapted to detect the occurrence of an acceleration and thus a downward deflection of the panel segment or the panel reference point or area. The duration of the acceleration and the point or time of the potential overshoot before the panel becomes steady-state under deflection or bending conditions can be determined.

[0011] Advantageously, the sensor device or module comprises a computing device for estimating the displacement or deflection or bending of the panel segment or the panel reference point or panel reference area by integrating, preferably time-integrating, the acceleration or accelerated movement. With the integration, the value or intensity of the deflection or bending in particular after the termination of the overshoot and after the stabilization under deflection or bending conditions can be calculated exactly. Further, having determined the value or intensity of the deflection or bending, an approximate weight estimation can be performed by means of a database, in particular a look-up table comprised therein.

[0012] A further or alternative embodiment of the sensor device or module is characterized by at least one strain gauge and / or extensometer placed on or assigned to the bottom surface of the panel and adapted to determine a value of the length extension of the bottom surface during a downward deflection or bending of the panel. The embodiment can further be characterized by a Wheatstone bridge circuit for estimating a strain resistance corresponding to the value of the strain level or the length extension. The length extension can be measured in at least one arbitrary direction at least when the at least one strain gauge and / or extensometer is positioned in a central area of the panel.

[0013] Preferably, at least a second strain gauge can be oriented in at least a second direction in order to improve the measurement. In the case of more than one strain gauge, it can be considered to provide a corresponding number of Wheatstone bridges, but a modification of the configuration of the Wheatstone bridge(s) accordingly can often be sufficient.

[0014] To further improve estimation accuracy, amplifiers can be assigned to or connected to sensor devices or modules, particularly strain gauges and / or to elongators and / or Wheatstone bridge circuits. As mentioned above, if a corresponding number of Wheatstone bridges should be considered in the case of more than one strain gauge, the number of amplifiers may also be related to the number of strain gauges and / or elongators and / or Wheatstone bridges. However, as stated above, since providing only modified Wheatstone bridges is usually sufficient in the case of at least two strain gauges, it is not necessary to provide more than one amplifier in this series.

[0015] In a preferred embodiment, the sensor device or module includes a significantly increased bridge voltage in the Wheatstone bridge circuit, which can be another measure to further improve estimation accuracy. Typically, the bridge voltage (also known as the “magnetizing voltage”) can have a value of 5V or 12V. The sensitivity of the bridge is strictly related to the voltage value; therefore, if the sensitivity would be insufficient, the excitation voltage will be increased accordingly. Another approach is to provide a significantly increased gauge factor for the strain gauge, preferably greater than 2. Many different types of strain gauges are available, differing primarily in the materials used to manufacture them. Their gauge factors can range from 2 (for inexpensive solutions) to approximately 16 (for more expensive solutions). Finally, for desired accuracy, low-noise amplifiers and / or rail-to-rail amplifiers and / or high-gain instrumentation amplifiers can also be used additionally or alternatively.

[0016] Another alternative embodiment of the sensor device or module provides an insert as a preferably removable cover or cap in a household appliance or a downdraft device or system supplied to that appliance, the insert being displaced or moved relative to a panel under the weight of the item to be weighed. The cover or cap is particularly an element of a downdraft cooking appliance.

[0017] Specifically, the sensor device is disposed between the cover portion and a collar for supporting the cover portion, wherein the collar is disposed at the panel and forms an upper frame for the filter element or filter inlet. Specifically, the sensor device is connected to the cover portion or the collar.

[0018] In order to enable the removal and / or replacement of the sensor device and / or the cover portion, magnetic and / or adhesive elements or other fixing elements or devices may be included for attaching the cover portion to the panel, particularly the collar, and / or attaching the sensor device to the cover portion or the collar.

[0019] Preferably, the sensor arrangement comprises a plurality of individual sensor elements, which are preferably between two and six, more preferably between two and four in number, spaced apart from each other on a circle, which are in particular subjected to equal weight load. Providing three individual sensor elements arranged on the corners of an equilateral triangle can provide an especially even weight distribution, as the cover portion or lid will rest evenly on said evenly spread individual sensor elements. Alternatively, four individual sensor elements can be provided in the corners of a rectangle, in particular a square. Providing more than just one individual sensor element can in particular improve the accuracy of the weight determination by comparing individual weight measurements. On the other hand, the more individual sensor elements are provided, the higher the cost of the overall arrangement will be. For cost saving purposes, it can be advantageous to arrange just one individual sensor element in a central region, for example in the center of the cover portion or lid of a downdraft device or system. In that case, said just one individual sensor element can rest on a central support element, for example on a diametric support rod instead of on a grommet.

[0020] A specific embodiment comprises a sensor arrangement which is electrically connected to a control unit of the downdraft device or system and / or of the downdraft cooking hob. At least one respective evaluation unit can be provided on a printed circuit board comprising said control unit. Alternatively, separate electronic circuits can be provided on a specific printed circuit board, which communicate with the user interface and / or power board circuit and / or control unit circuit or board only preferably via a MACS bus or the like.

[0021] The sensor arrangement can be of the capacitive pressure or piezoelectric pressure transducer type or of any other type known for weight measurement, in particular usable for small appliances, for example small household appliances.

[0022] According to an embodiment, the sensor arrangement or module according to any one of the preceding general or specific embodiments is part of or formed as an additional module for a household appliance. Said additional module is adapted such that the weight of an item placed on a surface of the household appliance, in particular of a cookware placed on a top surface of a cooking hob, is estimated.

[0023] The additional module can comprise a touch sensor or touch control user interface adapted to receive user input and / or a wireless communication arrangement configured to connect with a control unit of the household appliance.

[0024] This object is achieved by said household appliance according to the invention, which comprises at least a substantially horizontal panel.

[0025] The household appliance according to the application comprises an at least substantially horizontal panel, in particular a glass panel, which is part of or functionally connected with a scale for weighing an item placed on the panel. The household appliance further comprises or is adapted to be equipped with or coupled with a sensor device or module according to any one of the above basic or specific embodiments. The household appliance can be a cooking hob, in particular an induction cooking hob.

[0026] In particular, a control and / or processing unit is connected with the sensor device or module for controlling and / or retrieving data from the sensor device or module and / or for processing signals or data from the sensor device or module. The control and / or processing unit can comprise or be connected with a database and / or a look-up table and / or a cross-reference list, which can also be part of the database, for receiving at least approximate weight information associated with the determined displacement or deflection value.

[0027] According to a specific embodiment, the sensor device or module is arranged in a central region of the panel. In case of a cooking hob, the sensor device or module is arranged in a central region of a top plate of the cooking hob, and the cooking hob is adapted to determine the weight of a cookware by placing the cookware on said central region or on one of a plurality of cooking zones arranged on the top plate.

[0028] This object is achieved by a method according to the application for determining the weight of an item located on an at least substantially horizontal panel of a household appliance.

[0029] A method for determining the weight of an item located on an at least substantially horizontal panel, in particular a top plate of a cooking hob, of a household appliance, characterized in that an acceleration of a panel segment or a panel reference point or a panel reference area is estimated or determined during a displacement or deflection of the panel segment or the panel reference point or the panel reference area due to placing the item on the panel. The panel reference point or the panel reference area can be located or assigned to the panel surface. In particular, the estimation or determination of the weight is triggered by placing the item on the panel or by a user input.

[0030] In particular, the displacement or deflection or bending of the panel segment or the panel reference point or the panel reference area is estimated or determined by integrating, preferably time-integrating, the acceleration or the accelerated movement. With said integration, the value or intensity of the deflection or bending, in particular after a termination of an overshoot and after a stabilization under deflection or bending conditions, can be calculated exactly. Further, having determined the value or intensity of the deflection or bending, an approximate weight estimation can be performed by means of a database, in particular a look-up table comprised therein.

[0031] The estimated or determined weight information can be displayed on a display device, which can be a user interface of the household appliance or sensor device or module. As an alternative, the weight information can be processed during an operating process running in the household appliance, in particular during a cooking process performed on the cooking hob.

[0032] The novel and inventive features of the present application are set forth in the appended claims.

[0033] The present application will be described in further detail with reference to the accompanying drawings, in which:

[0034] Figure 1 is a schematic top view of an induction cooking hob with four cooking zones, a user interface and an acceleration sensor for weight determination;

[0035] Figure 2 is Figure 1 is a schematic sectional view of the induction cooking hob according to

[0036] Figure 3 is Figure 2 is a schematic detailed view of the detail III indicated in

[0037] Figure 4 is a schematic sectional view according to Figure 1 but wherein a cooking pot is placed on the center zone of the top panel of the induction cooking hob for determination of the pot weight;

[0038] Figure 5 shows a schematic structure of the acceleration sensor applied within the induction cooking hob according to Figure 1

[0039] Figure 6 is Figure 3 a detailed view of

[0040] Figure 7 is Figure 6 a detailed illustration of the light interrupter of

[0041] Figure 8a shows the top panel of the induction cooking hob under the stress of a sample weight, illustrating the determination of the pot weight according to the third embodiment;

[0042] Figure 8b shows the components of the evaluation circuitry for weight determination according to the third embodiment;

[0043] Figure 9 ​The sensor positioning of a fourth embodiment for making a pot weight determination is schematically shown; and

[0044] Figure 10 A schematic representation of a disassembly arrangement of the device is shown. Figure 9

[0045] With both Figure 1 and Figure 2 a schematic representation of an induction cooking hob 1 is shown in a top view and in a cross-sectional view along the line II-II indicated in Figure 1 The four cooking zones A, B, C, D are arranged in a rectangular manner on the glass-ceramic top panel 3. Each cooking zone A, B, C, D is heated by an induction coil 5 arranged close to the bottom surface 7 of the top panel 3. The induction cooking hob 1 is further equipped with a user interface 9 positioned at the front edge of the induction cooking hob 1. The induction cooking hob 1 further comprises an accelerometer 11, i.e. an acceleration sensor. Said accelerometer 11 is configured to determine and / or measure an acceleration in vertical direction in the center of the top panel 3 during or due to an impact by a manual or mechanical action acting on the top side 13 of the top panel 3 or by an impact by a load like a cooking pot 15 filled with food placed on the top panel 3, which can be a vibration or just an accelerated downward movement.

[0046] The user interface 9 comprises a touch-sensitive display which is adapted to receive user inputs for operating the cooking zones A, B, C, D and to display information, e.g. status information of the cooking zones A, B, C, D. The user can operate the cooking zones A, B, C, D by touching switches A', B', C', D', each of which is assigned to one of the cooking zones A, B, C, D. Further touch switches 17 for other hob functions are included.

[0047] Figure 3 A detailed view showing a schematic representation of the wiring required for one of the cooking zones A, B, C, D and its operation. This illustration can also be seen as a basic configuration for an example of the induction cooking hob 1 using only one cooking zone A, B, C, D. Figure 3 ​A, B, C, D. The cooking zones A, B, C, D are exposed to electromagnetic waves emitted from an induction coil 5 located below the cooking zones A, B, C, D, which induce eddy currents in the bottom of a cooking pot 15 on the cooking zones A, B, C, D, with the effect of heating said pot bottom. A thermal sensor 19 is located in the area of the cooking zones A, B, C, D, such as a thermostat providing temperature information of this area. Further, an induction generator 21 of magnetic waves is shown, which is connected to a controller 23, which controls the signal generated by the generator 21 and the energy of the signal. Also shown is a user interface controller 25, which is connected to the controller 23 and to an accelerometer 11, which in the present example is a microelectromechanical system (MEMS). As shown, the microelectromechanical system 11 is indirectly attached to the induction cooking hob 1 via a dielectric shield 27, which can be made of a mica mineral as a hard substance, so that it does not significantly dampen vibrations and protects the microelectromechanical system 11 from the electromagnetic waves emitted by the induction coil 5 or from the electric field established during operation or present at the induction cooking hob 1. At the same time, mica also provides good thermal insulation against heat transferred from the hot cooking pot 15 through the glass-ceramic top panel 3.

[0048] The above arrangement serves to determine the weight of the cooking pot 15, in particular of its contents, in particular for weighing newly added ingredients. As Figure 4 As shown, placing a cooking pot 15 causes the top panel 3 of the induction cooking hob 1 to bend or deflect downwards due to the weight of the cooking pot 15 (exaggerated for clarity reasons). The size of the bending or deflection depends on the weight value, so that the actual weight can be determined by measuring said bending or deflection size, which is a reproducible process. Said bending or deflection measurement is performed by time-integrating the acceleration or accelerated movement of a reference area in the central area of the top panel 3 by means of the accelerometer 11 or MEMS, respectively, which is also the fixed position of the accelerometer 11, and is displayed on the top surface 13 of the top panel 3 as a defined weighing area of the induction cooking hob 1.

[0049] Figure 5The structure of the MEMS acceleration sensor 11 is schematically shown, which is of the gravitation sensor type. Basically, the MEMS structure provides three stacked plates 29a, 29b, 29c connected to each other by means of a spiral spring 31. The upper and lower plates 29c, 29a are fixed and the middle plate 29b is movable, but its mobility is limited by the spiral spring 31. This arrangement provides a series connection of two capacitors 33 with variable capacitance due to the variable distance of the double plates 29a-29b, 29b-29c following the movement of the middle plate 29b. In the case of no movement or constant movement, the plates 29a, 29b, 29c are in equidistant arrangement, but in the case of accelerated movement of the acceleration sensor 11, the middle plate 29b moves due to its moment of inertia. The occurring capacitance change is proportional to the acceleration and integrating the actual capacitance allows to deduct the included deflection.

[0050] In Figure 6 a second embodiment for determining the weight of the cooking pot 15 is shown. The structure of this embodiment is similar to the first embodiment and is easily understood when comparing it with Figure 3 The weight determination according to the second embodiment also relies on measuring the magnitude of the displacement or deflection of the top panel 3 of the induction cooking hob 1 under the cooking pot weight load, similar to the practice of the first embodiment. However, the displacement or deflection is determined by means of an optical device comprising a light sensor or light interrupter 35. There are several types of such optical sensors known, which usually operate with a light emitting element 37 and a light receiving element 39. Two basic types of light interrupters 35 are the transmissive (gap) type and the reflective type. The transmissive type is easier to operate, as all optical elements 37, 39 are already adjusted. The signal is generated by interrupting the light on its way from the light emitting element 37 to the light receiving element 39 by an obstacle. The reflective type light interrupter 35 requires a reflective surface 41 for reflecting the light emitted from the light emitting element 37. As the light emitting element and the light receiving element 37, 39 face the same direction, the distance of the reflective surface 41 to the reflective type light interrupter 35 is determined by the duration or transit time of the emission and reception of the light signal.

[0051] In the present example, a reflective type light interrupter 35 is used. Figure 7The example of this sensor type shown in Fig. 3 is adapted to be mounted on a printed circuit board, which can be fixed on an inner housing or compartment structure inside the induction cooking hob 1, in particular on or at the carrier part of at least one induction coil 5 or on a protective box of the electronic components and circuit boards of the induction cooking hob 1. In general, the fixation can be arbitrary chosen, only it has to be ensured that the fixation position is chosen detached from the top panel 3. The light interrupter 35 comprises a housing 43, the light emitting element 37, the light receiving element 39 and two ports 45 for each of the elements. Via these ports 45, an electronic unit located on the printed circuit board and an associated software, the above mentioned duration or transit time between the emission and the reception of the light signal, which is reflected from the reflective surface 41 located on the bottom surface 7 of the top panel 3, can be identified, see Fig. 3. Figure 6 The main output of the light interrupter 35 is an analog signal, which is interpreted by the software. In order to measure the duration or transit time without failure, a sufficient distance between the light interrupter 35 and the top panel 3 has to be chosen. The reflective surface 41 located on the bottom surface 7 of the top panel 3 can be applied by a regular printing on a glass ceramic surface or by droplets of a color, in particular white. For thermal reasons, it is proposed to apply a stencil on the glass surface to have a certain distance.

[0052] Figure 8a A third embodiment of a weight determination of the cooking pot 15 by means of a top panel displacement or deflection is demonstrated by showing an experimental arrangement. In this figure, the weight load provided by the cooking pot 15 is simulated by a sample weight 47 placed on a glass ceramic top panel 3 as used in an induction cooking hob 1. The scale integrated in the induction cooking hob 1 comprises a strain gauge 49, which is attached to the bottom surface 7 of the top panel 3 by means of a glue 51. Due to this fixed attachment, the strain gauge 49 follows the bottom surface 7 in its extension or elongation, respectively, which occurs when the top panel 3 is bent or deflected downwards. The elongation applied on the strain gauge 49 causes a resistance change, which can be measured by applying a voltage thereon or, as a more reliable method, using an evaluation circuit 53 comprising a Wheatstone bridge 55 and an instrument amplifier 57 (see Fig. 4). Figure 8b ) works as follows: when the strain gauge 49 is under stress, i.e. deflection causing elongation, there is a resistance change of the strain gauge 49, which changes the voltage measurable at the Wheatstone resistance bridge 55. This voltage as a voltage input V in is transmitted to the instrument amplifier 57, which amplifies the voltage V in , in this respect increasing the readability and accuracy of the measurement. In this respect, the strength of the resistance change of the strain gauge 49 and the voltage output Vout proportional to the size of the elongation of the strain gauges and, thus, to the size of the deflection of the top panel. In that way, the weight of the cooking pot 15 can be determined with high accuracy.

[0053] More generally, the Wheatstone bridge 55 serves to convert a change in strain resistance into a change in voltage. However, since the voltage output of the Wheatstone bridge 55 is usually too small to be used for analyzing the change, an amplifier 57 for amplifying the voltage output can be required. The estimation process for selecting a suitable amplifier depends on a number of different parameters. In many cases, it is convenient to select an instrumentation amplifier 57.

[0054] According to Figure 8a , the voltage output is transmitted to an estimation circuit 53, in particular to an electronic component within the user interface 9, which displays the weight of the cooking pot 15, for example on a user interface display, after conversion by means of an index table in a database of the induction cooking hob 1.

[0055] Finally, with Figure 9 and Figure 10 a fourth embodiment is shown which uses a scale integrated in the induction cooking hob 1 for weight determination of the cooking pot 15. In this example, the entire top panel 3 is not displaced or deflected, but an insert arranged or arrangeable in a cut-out region of the top panel 3 is displaced or moved relative to the top panel 3 under the weight of the item to be weighed. In Figure 9 and Figure 10 the present example discloses a cover portion 59 of a downdraft device or system, in particular a cover 59 of a downdraft exhaust system 61 implemented in the central region of the cooking hob 1. The cover 59 is removable for disassembly of the filter unit 63, as Figure 10 is shown, which shows the disassembled cover 59 and the cylindrical filter cartridge 63.

[0056] As Figure 9 is shown, the downdraft exhaust system 61 is arranged in a cut-out 65 of the central region of the cooking hob 1. The downdraft exhaust system 61 comprises a cylindrical exhaust compartment 67 comprising the cylindrical filter cartridge 63. The upper frame 69 of the cylindrical exhaust compartment 67 arranged close to the circular cut-out 65 of the top panel center also forms a collar for supporting the cover 59 and provides support for the three weight sensors 71 arranged on the corners of an equilateral triangle. In that way, the weight sensors 71 are pressed between the cover 59 and the upper frame 69 of the exhaust compartment 67.

[0057] The weight sensors 71 are preferably fixed to the upper frame 69 of the exhaust compartment 67, which allows them to be connected by wired connection to the controller 23 or to the user interface 9 of the cooking hob 1. However, it is also possible to couple them to the cover 59, in particular when they are equipped with wireless communication means for communicating with the controller 23 or the user interface 9.

[0058] While illustrative embodiments of the application are described herein with reference to the accompanying drawings, it is to be understood that the application is not limited to that precise embodiment, and that various other changes and modifications can be affected therein by those skilled in the art without departing from the scope or spirit of the application. All such changes and modifications are intended to be included within the scope of the application as defined by the appended claims. In particular, the above examples are all described with reference to an induction cooking hob 1, but the application is not limited to this type. On the contrary, all other types of cooking hobs are also to be included, such as radiant or gas hobs.

[0059] List of reference signs

[0060] 1 induction cooking hob

[0061] 3 top panel

[0062] 5 induction coil

[0063] 7 bottom surface

[0064] 9 user interface

[0065] 11 accelerometer

[0066] 13 top side / top surface

[0067] 15 cooking pot

[0068] 17 touch switch

[0069] 19 heat sensor

[0070] 21 induction generator

[0071] 23 controller

[0072] 25 user interface controller

[0073] 27 dielectric shield

[0074] 29a, 29b, 29c plate

[0075] 31 coil spring

[0076] 33 capacitor

[0077] 35 optical interrupter

[0078] 37 light emitting element

[0079] 39 light receiving element

[0080] 41 reflective surface

[0081] 43 housing

[0082] 45 port

[0083] 47 sample weight

[0084] 49 strain gauge

[0085] 51 glue

[0086] 53 estimation circuit

[0087] 55 Wheatstone bridge

[0088] 57 instrumentation amplifier

[0089] 59 covering portion / cover

[0090] 61 under-suction exhaust system

[0091] 63 filter cartridge

[0092] 65 cutout

[0093] 67 exhaust compartment

[0094] 69 upper frame

[0095] 71 weight sensor

[0096] A, B, C, D cooking zone

[0097] A', B', C', D' touch switch

[0098] V in , V out input voltage, output voltage

Claims

1. A sensor device or module for determining the weight of an item located on a panel (3) or on an insert relative to the panel (3), the sensor device or module and the panel (3) forming a weighing device, the sensor device or module - being adapted to be integrated in or distributed to a household appliance (1), and - comprising or being connected to at least one processing and / or interpreting and / or compiling device for increasing the sensor sensitivity and / or the estimation unit accuracy, wherein the sensor device or module comprising: a light sensor (35) configured for measuring the distance from a reference point or a reference area on the surface of the panel (3), wherein the light sensor (35) is a reflective light sensor and the reference point or the reference area comprises a reflective surface (41) which is one of a glossy surface of the panel, a printed glass surface and a surface of a color droplet or a print applied on the panel surface; and an acceleration sensor (11) for detecting the acceleration of a reference point or a reference area on the surface of the panel (3) during an elastic displacement or deflection or bending of the reference point or the reference area due to the placement of an item (15) to be weighed on the panel (3).

2. The sensor device or module according to claim 1, characterized in that the light sensor (35) is positioned below the panel (3) and / or is a light interrupter.

3. The sensor device or module according to claim 2, characterized in that the light sensor (35) is arranged or can be arranged away from the panel (3), the light sensor (35) being arranged or can be arranged at a housing or frame portion of the household appliance (1) or of a component or module arranged inside the household appliance (1).

4. The sensor device or module according to claim 3, characterized in that the light sensor (35) is applied on a printed circuit board connected or fixed to the housing or the frame portion.

5. The sensor device or module according to claim 1, characterized in that the reference point of the panel or the reference area of the panel is a reference point or a reference area located on the panel surface.

6. The sensor device or module according to claim 5, characterized in that the sensor device or module further comprises a computing device for estimating the displacement or deflection or bending of the panel reference point or panel reference area by integrating the acceleration or accelerated movement.

7. The sensor device or module according to any one of claims 1 to 6, characterized in that - at least one strain gauge (49) and / or extensometer placed on or distributed to the bottom surface (7) of the panel (3) and adapted to determine the value of the length extension of the bottom surface (7) during the downward deflection or bending of the panel (3), and in that - a Wheatstone bridge circuit (55) for estimating the strain resistance corresponding to the value of the strain level or the length extension.

8. Sensor device or module according to claim 7, characterized in that an amplifier (57) is assigned to or connected to the strain gauge (49) and / or the extensometer and / or the Wheatstone bridge circuit (55).

9. Sensor device or module according to claim 7, characterized in that at least one of the following: - an apparent increased bridge voltage (V in ) of the Wheatstone bridge circuit (55), the bridge voltage being for an excitation voltage, the bridge voltage being in the range of 5 V to 12 V; - a significantly increased strain coefficient of the strain gauge (49), which is in the range of 5 to 16; - a low-noise amplifier and / or a rail-to-rail amplifier and / or a high-gain instrumentation amplifier (57).

10. Sensor device or module according to claim 1 characterized in that the insert is a removable cover portion of a downdraft device or system (61) in or assigned to the domestic appliance (1), which is displaced or moved relative to the panel (3) under the weight of the article (15) to be weighed.

11. Sensor device or module according to claim 10, characterized in that the sensor device is arranged between the cover portion (59) and a collar (69) for supporting the cover portion (59), which is arranged at the panel (3) and forms an upper frame of a filter element or filter inlet or filter chamber (67), the sensor device being coupled with the cover portion (59) or the collar (69).

12. Sensor device or module according to claim 10, characterized in that the sensor device is arranged between the cover portion (59) and a support element providing support for the sensor device, which is a diametric support strut, the support element being located in a central region on a center axis of the downdraft device or system (61).

13. Sensor device or module according to claim 11 or 12, characterized in that magnetic and / or adhesive elements or other fixing elements or means are included for removably adhering the cover portion (59) at the panel (3) and / or the sensor device at the cover portion (59) or the collar (69) or the support element.

14. Sensor device or module according to any one of claims 1 to 6, which is part of a domestic appliance (1) or formed as an additional module for the domestic appliance for estimating the weight of an article (15) placed on a surface of the domestic appliance (1).

15. Sensor device or module according to claim 14, characterized in that the additional module comprises: - a touch sensor or touch control user interface adapted to receive user input, and / or - a wireless communication device configured to connect with a control unit of the domestic appliance (1).

16. The sensor device or module of claim 1, wherein, The panel is a glass panel or a glass-ceramic panel.

17. The sensor device or module of claim 1, wherein, The domestic appliance is a cooking hob.

18. The sensor device or module of claim 1, wherein, The domestic appliance is an induction cooking hob.

19. The sensor device or module of claim 1, wherein, The displacement or deflection or bending is an elastic displacement or deflection or bending.

20. A domestic appliance comprising: at least approximately horizontal panel (3) being part of or functionally connected with a scale for weighing an item (15) placed on the panel (3), the household appliance (1) further comprising or being adapted to be equipped with or coupled with a sensor arrangement or module according to any one of claims 1 to 19.

21. Household appliance according to claim 20, characterized in that a control and / or processing unit is connected with the sensor arrangement or module for controlling and / or retrieving data from the sensor arrangement or module and / or for processing signals or data from the sensor arrangement or module, the control and / or processing unit (23) comprising or being connected with a look-up table and / or cross-reference list for receiving at least approximate weight information associated with the determined displacement or deflection value.

22. Household appliance according to claim 20 or 21, characterized in that the sensor arrangement or module is arranged in a central area of a top plate of a cooking hob, the cooking hob being adapted to determine a weight of a cookware by placing the cookware on one of the central area or a plurality of cooking zones (A, B, C, D).

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