DE102013019648B4 - Input device for an electronic household appliance - Google Patents

Abstract

An input device for a home electronic appliance, comprising: an electrically non-conductive support (12); and at least one first sensing electrode (14, 14a, 14b) of electrically conductive material and at least one second sensing electrode (16, 16a, 16b) of electrically conductive material electrically isolated from each other (18, 18a, 18b, 18c) on the support (12), wherein the at least one first measuring electrode (14, 14a, 14b) and the at least one second measuring electrode (16, 16a, 16b) in the non-actuated output state of the input device have different electrical potentials and electrically by an operation of the input device characterized in that the at least one first measuring electrode (14) and the at least one second measuring electrode (16a, 16b) are electrically isolated (26) from the user; the at least one first measuring electrode (14) upon actuation of the input device is movable relative to the at least one second measuring electrode (16a, 16b); anda sensor circuit (20) for detecting a potential change of the at least one first measuring electrode (14, 14a, 14b) and / or the at least one second measuring electrode (16, 16a, 16b) is provided.

Description

The present invention relates to an input device for a household electronic appliance, as well as an electronic household appliance with at least one such input device.

In many electrical or electronic devices, especially in household appliances such as stoves, hobs, microwave ovens, dishwashers, washing machines, dryers, refrigerators and / or freezers and the like, contact-sensitive and / or proximity-sensitive input devices or proximity switches are frequently used which, for example, trigger a certain operation and / or change a device setting ("touch control") by a simple touch or approach by a user's finger. Such touch and / or proximity sensitive input devices often employ capacitive sensor elements and sensor circuits.

Rotary knob type input devices using capacitive sensor elements and sensor circuits are known in the art, for example US 2006/0158041 A1 and the US 2009/0009491 A1 known.

The US 5,844,204 A shows an iron, in the grip of two electrical contacts are present, which are electrically isolated from each other and which are connected to two different potentials of an electronic detector circuit. When a user grips the iron with his hand on this handle, the two contacts are short-circuited or grounded by hand, whereby an electrical signal is generated by the detector circuit. The detector circuit may thus detect whether the iron is gripped by a user and, if necessary, trigger or unlock a predetermined function.

It is the object of the invention to provide an improved input device for electronic household appliances with electromagnetic compatibility (EMC).

This object is achieved by an input device having the features of claim 1. Particularly preferred embodiments and further developments of the invention are the subject of the dependent claims.

The input device of the invention comprises an electrically non-conductive support and at least one first measuring electrode made of an electrically conductive material and at least one second measuring electrode made of an electrically conductive material, which are arranged electrically isolated from one another on the support and electrically insulated from the user , The at least one first measuring electrode and the at least one second measuring electrode have different electrical potentials in the non-actuated output state of the input device and are electrically conductive to each other by an actuation of the input device, in which the at least one first measuring electrode is movable relative to the at least one second measuring electrode connectable. A sensor circuit is provided to detect a potential change of the at least one first measuring electrode and / or the at least one second measuring electrode.

In an input device configured in this way, the first and second measuring electrodes are at different electrical potentials and can be electrically conductively connected to one another and thus short-circuited by an actuation of the input device. A potential change of the first and / or second measuring electrodes generated thereby can be detected by the sensor circuit in order to conclude from this an actuation of the input device. The variation of electrical potentials or potential differences is much less sensitive to (internal and external) electrical and electromagnetic influences compared to capacitance changes in conventional touch and / or proximity sensitive input devices with capacitive sensing elements. The input device of the invention thus has a significantly improved electromagnetic compatibility (EMC) without the need for special technical measures (for example shielding, higher-value components, etc.). The advantage of improved EMC can be achieved with simple components and a simple structure. Nevertheless, a very reliable operation of the input device can be achieved.

The carrier in this context is intended to designate a structural component which is suitable for arranging the first and second measuring electrodes at predetermined positions. The size and shape of the carrier preferably also determine the size and shape / design of the input device or at least its operating section. Depending on the configuration of the carrier, the input device preferably contains an operating section in the form of a rotary knob, a door handle, a slide control, a push-button arrangement or the like. The carrier is made of an electrically insulating material or provided with an electrically insulating coating. The carrier is preferably made of a plastic material. The carrier may be configured in one or more parts. The first and second measuring electrodes are preferably fixed to the carrier (permanent or detachable).

In this context, a measuring electrode should be understood to mean a structural component which defines a measuring surface or contact surface (basically any shape and size). The measuring electrodes are made of an electrically conductive material, preferably of a metal or an electrically conductive plastic material. The measuring electrodes are preferably designed plate-shaped, optionally or depending on the shape of the carrier substantially planar or one or more times curved, or designed block-like.

The first and second measuring electrodes are at different electrical potentials in the non-actuated output state of the input device. Preferably, the first and second measuring electrodes are electrically separated from each other and connected to different poles of a DC voltage source or to different DC voltage sources. The potential difference (s) is / are preferably in the range of a few volts.

By actuating the input device, the first and second measuring electrodes can be connected to one another in an electrically conductive manner. Such a short-circuiting of the measuring electrodes equalizes their potentials, i. the electrical potentials of the measuring electrodes and the electrical potential difference between the measuring electrodes change. The operation of the input device is preferably accomplished by touching the input device, applying pressure to the input device, moving a portion of the input device relative to another portion of the input device, or a combination of such operations.

The sensor circuit may preferably detect changes in the electrical potentials of the first measuring electrodes, the second measuring electrodes, the first and second measuring electrodes or the electrical potential differences between the first and second measuring electrodes. This registration can be direct or indirect. Thus, the sensor circuit is preferably designed to detect at least one measured variable which is selected from a potential difference, a resistance, a current flow, a temporal change of a potential difference, a temporal change of a resistance and a temporal change of a current flow between the at least one first measuring electrode and the at least one second measuring electrode. The sensor circuit is preferably arranged in or on the carrier. The sensor circuit preferably forms a structural unit with the carrier and the measuring electrodes. The sensor circuit is wireless or wired connected to a transmitter and / or a controller, for example, a household appliance. The sensor circuit itself preferably detects only the measured values of the potential changes, for the further evaluation preferably a separate evaluation electronics is provided, which is preferably connected to a controller, for example of the household appliance or integrated into such.

In a preferred embodiment of the invention, the sensor circuit has a voltage divider with a series circuit of a fixed resistor and a variable resistor, wherein the variable resistor has a variable by an operation of the input device resistance value. In the non-actuated output state of the input device, the variable resistor preferably has a resistance value against infinity (electrically isolated). Upon actuation of the input device, the variable resistance value may preferably fall within a range of only a few MΩ or even only a few kΩ.

In a preferred embodiment of the invention, at least two first measuring electrodes and / or at least two second measuring electrodes are provided. The first and the second measuring electrodes can be present in the same or in different numbers. The first measuring electrodes are then electrically insulated both from one another and from the second measuring electrodes, and the second measuring electrodes are then electrically insulated both from each other and from the first measuring electrodes. In the case of a plurality of first measuring electrodes, these may have the same or different potentials to one another; In the case of a plurality of second measuring electrodes, these may have the same or different potentials. Overall, the plurality of first and / or second measuring electrodes can thus have two or more different potentials. The numbers of the first and second measuring electrodes depend in particular on the shape and the size of the carrier and the desired measuring accuracy of the input device.

Preferably, the sensor circuit is designed to detect potential changes to a plurality of pairs of one of the first measuring electrodes and one of the second measuring electrodes in chronological succession (for example by multiplexing) or in parallel (for example by a correspondingly large number of sensor circuit branches).

According to the invention, the at least one first measuring electrode and the at least one second measuring electrode are electrically insulated from the user and the at least one first measuring electrode is movable relative to the at least one second measuring electrode when the input device is actuated. The measuring electrodes, the In the non-actuated initial state of the input device are at different electrical potentials, can be short-circuited by a relative movement of the at least one first measuring electrode. The resistance value of the above-mentioned variable resistor of the sensor circuit is determined in this case upon actuation of the input device by the local conditions which have changed due to the relative movement of the measuring electrodes relative to one another.

Preferably, upon actuation of the input device, a distance between the at least one first measuring electrode and the at least one second measuring electrode is variable. A reduced distance usually results in a reduced resistance, which can be detected by the sensor circuit.

In a preferred embodiment, at least two second measuring electrodes are provided and the (exactly) a first measuring electrode is configured in the shape of an annular ring and the at least two second measuring electrodes are arranged in a surrounding manner. In this case, the one first measuring electrode is preferably rotatable in its circumferential direction relative to the at least two second measuring electrodes.

In yet another preferred embodiment of the invention, the at least one first measuring electrode and / or the at least one second measuring electrode along a circle or a circular arc are arranged one behind the other. In another preferred embodiment of the invention, the at least one first measuring electrode and / or the at least one second measuring electrode are arranged essentially in a straight line one behind the other.

The invention also relates to an electronic household appliance with at least one input device of the invention described above. The household appliance is preferably a laundry treating appliance (e.g., washing machine, clothes dryer, etc.), a dishwasher, a cooking utensil (e.g., hob, stove, microwave oven, etc.), a refrigerator and / or freezer, or the like. In the case of multiple input devices of the invention, these may be the same or different from each other.

• 1A eine Querschnittsansicht einer Eingabevorrichtung für ein elektronisches Haushaltsgerät;
• 1 B eine Schemadraufsicht der Eingabevorrichtung von 1A;
• 2 eine Darstellung einer Sensorschaltung mit Einfeldauswertung für die Eingabevorrichtung von 1;
• 3 eine Darstellung einer Sensorschaltung mit Mehrfeldauswertung für die Eingabevorrichtung von 1;
• 4 eine Seitenansicht einer anderen Eingabevorrichtung für ein elektronisches Haushaltsgerät; und
• 5 eine Schemadraufsicht einer Eingabevorrichtung gemäß einem Ausführungsbeispiel der Erfindung.

The above and other features and advantages of the invention will become more apparent from the following description of preferred, non-limiting embodiments with reference to the accompanying drawings. In it show, mostly schematically:

• 1A a cross-sectional view of an input device for a household electronic device;
• 1 B a schematic top view of the input device of 1A ;
• 2 a representation of a sensor circuit with single-field evaluation for the input device of 1 ;
• 3 a representation of a sensor circuit with multi-field evaluation for the input device of 1 ;
• 4 a side view of another input device for a household electronic device; and
• 5 a schematic plan view of an input device according to an embodiment of the invention.

Based on 1 to 3 The basic principle of the sensor circuit for an input device according to the invention will now be explained in more detail using the example of another touch-sensitive rotary knob.

The knob is, for example, on a control panel 10 an electronic home appliance attached. The knob has a carrier 12 made of an electrically non-conductive plastic material, which dictates the shape and size of the knob (see. 1A) , On the substantially cylindrical outer circumferential surface, the rotary knob provides an operating section in / on which a plurality of first measuring electrodes 14 and a plurality of second measuring electrodes 16 arranged and on the carrier 12 are attached.

As in 1A In this example, a total of five first measuring electrodes are illustrated 14 and five second measuring electrodes 16 arranged alternately one behind the other along a circular ring. The measuring electrodes 14 . 16 are each made of an electrically conductive material (eg metal, electrically conductive plastic) and by electrical insulation 18 separated from each other. The measuring electrodes 14 . 16 For example, in pockets or recesses of the wearer 12 be absorbed so that the walls between the recesses the insulation 18 form.

The first measuring electrodes 14 each have a first electrical potential, and the second measuring electrodes each have a second electrical potential that is different from the first electrical potential. The potential difference between the first and the second electrical potential and thus between the first and the second measuring electrodes 14 . 16 For example, it is on the order of 1.5V to 5V is for example about 3.3 V. The different electrical potentials of the first and second measuring electrodes 14 . 16 Thus, for example, by a DC voltage source 101 be provided in the form of simple batteries (see. 2 ).

As in 1B are indicated, the first and second measuring electrodes 14 . 16 arranged in pairs opposite each other so that they are picked up by a user with two fingers 22a . 22b one hand can be contacted at the same time. By such operation of the input device, the first and second measuring electrodes 14 . 16 a pair of measuring electrodes shorted over the user's hand, resulting from a sensor circuit 20 between the first and second measuring electrodes 14 . 16 can be detected.

The first and second measuring electrodes 14 . 16 are via a sensor circuit 20 connected in pairs with a corresponding number of circuit branches and placed on the different electrical potentials, as in 1A and 1B indicated.

A possible construction of such a sensor circuit 20 for a circuit branch between a first measuring electrode 14 and a second measuring electrode 16 is in 2 shown.

The sensor circuit 20 contains a DC voltage source 201 (eg battery), which on the one hand with the first measuring electrode 14 electrically connected and on the other hand via a fixed resistor 202 with the second measuring electrode 16 is electrically connected. Parallel to the fixed resistor 202 is a voltmeter (eg voltmeter) 204 switched, with which the voltage drop across the fixed resistor 202 can be detected.

In the non-actuated initial state of the input device are the two electrically isolated from each other measuring electrodes 14 . 16 at different electrical potentials, which by the DC voltage source 201 are predetermined. Upon actuation of the input device in the in 1B illustrated manner, the two measuring electrodes 14 . 16 over the finger touching the knob 22a . 22b short circuited by a user, so that forms a closed circuit, over which the electrical potentials of the two measuring electrodes 14 . 16 can match.

As in 2 shown, the sensor circuit 20 upon actuation of the input device, a voltage divider consisting of said fixed resistor 202 and another variable resistor 203 is formed. The resistance of the variable resistor 203 goes in the non-actuated output state of the input device, ie without touching the fingers 22a . 22b , against infinity. When contacting the measuring electrodes 14 . 16 as in 1B reduces the resistance of the variable resistor 203 for example, about 200 kΩ to about 1.5 MΩ (depending on the state of the user's hand).

Over the fixed resistor 202 , which has a resistance value of about 10 MΩ, for example, then drops a voltage in the range up to about 3.2 V through the current flowing in the closed circuit current I of about 0.5 - 0.6 uA, which by the voltmeter 204 can be detected.

In one embodiment, the sensor circuit 20 five such circuit branches, each comprising a pair of opposing first and second measuring electrodes 14 . 16 interconnect with each other. The sensor circuit 20 In this way, the potential changes in potential at the different pairs of first and second measuring electrodes can be recorded in parallel in time.

3 shows another embodiment of the sensor circuit 20 with which the potential changes in potential at the different pairs of first and second measuring electrodes 14 . 16 can be detected in the multiplex process in chronological order.

The sensor circuit of 3 points like the sensor circuit of 2 a DC voltage source 201 , a solid resistance 202 and a voltmeter 204 on. The multiple pairs of first measuring electrodes 14 and second measuring electrodes 16 are connected in parallel with each other, wherein a first pole of the DC voltage source 201 each via a first switching element 205 with one of the first measuring electrodes 14 is connectable and a second pole of the DC voltage source 202 each above the fixed resistance 202 and a second switching element 206 with one of the second measuring electrodes 16 is connectable. By closing the first and second switching elements 205 . 206 can the variable resistors 203 between the first and second measuring electrodes 14 . 16 be recorded one after the other.

In the embodiment of 3 not only the variable resistances can do this 203 between opposing first and second measuring electrodes 14 . 16 but in principle all possible combinations between one of the first measuring electrodes 14 and one of the second measuring electrodes 16 , Alternatively, it is also possible, the first switching elements 205 or the second switching elements 206 to omit only the variable resistors 203 between opposite pairs of first and second measuring electrodes.

With the aid of the described arrangement of first and second measuring electrodes 14 . 16 and the described sensor circuit 20 can be at the knob the position of the touch by the fingers 22a . 22b be recognized by the user and, for example, a corresponding washing or cooking program can be selected. In addition, there is also the possibility of a rotational movement of the fingers 22a . 22b to recognize around the knob (eg by a temporal sequence of potential changes to different pairs of measuring electrodes), for example, to make a change in a set parameter of a washing or cooking program. In principle, both absolute rotational positions of the fingers and relative rotational movements can be detected. The more first and second measuring electrodes 14 . 16 are provided on the rotary knob, the greater the accuracy and variety of input operations can be on the knob.

In the example of 1 and 3 lie all first measuring electrodes 14 at the same first electrical potential and are all second measuring electrodes 16 at the same second electrical potential. However, it is also possible to use the several first measuring electrodes 14 to set to different electrical potentials and / or the multiple second measuring electrodes 16 to set different electrical potentials. In such an embodiment, if necessary, a plurality of DC voltage sources are provided to provide the more than two different potentials.

In the example of 1 and 3 contains the sensor circuit 20 a voltmeter 204 for voltage detection. Alternatively, the sensor circuit may also comprise a plurality of voltmeters for voltage detection, one or more ammeter for current detection, one or more measuring devices for resistance measurement or combinations of said options. In particular, the changes in the potentials or potential differences can be detected either directly via voltage measurements or indirectly via the measurements of other electrical variables.

Referring to 4 Now, another example of an input device for a home electronic appliance will be described in more detail.

In this example, the input device is configured in the manner of a door handle. The electrically non-conductive carrier 12 is shaped and dimensioned accordingly.

At one of the door 24 facing away from the outside of the carrier 12 are several (here: three) first measuring electrodes 14a . 14b arranged. At one of the door facing the inside of the carrier 12 are several (here: three) second measuring electrodes 16a . 16b ) arranged. As in the first example, the first and second measuring electrodes are located 14a . 14b . 16a . 16b free for the user so that they can be directly contacted by the user when he / she grasps the door handle with his / her hand.

The first measuring electrodes 14a . 14b are arranged substantially straight behind one another, and the second measuring electrodes 16a . 16b are essentially arranged in a straight line one behind the other. In addition, the first and second measuring electrodes are located 14a - 16a . 14b - 16b in pairs opposite each other. The first measuring electrodes 14a . 14b are through insulation 18a electrically isolated from each other, the second measuring electrodes 16a . 16b are through insulation 18b electrically isolated from each other, and the first measuring electrodes 14a . 14b are from the second measuring electrodes 16a . 16b through insulation 18c electrically isolated. The different insulations 18a . 18b . 18c For example, ribs may be formed from an electrically conductive material attached to the carrier 12 attached or formed integrally therewith.

As indicated by the reference numbers in 4 indicated, lie the plurality of first measuring electrodes 14a . 14b at different potentials and are the several second measuring electrodes 16a . 16b on different potentials. In addition, the first and second measuring electrodes of a pair lying opposite to each other at different potentials. In the specific example of 4 lie the two outer first measuring electrodes 14a and the one inner second measuring electrode 16b at a first electrical potential and are the one inner first measuring electrode 14b and the two outer second measuring electrodes 16a at a second electrical potential. In this case, the electrical potentials of all the first and second measuring electrodes by a single DC voltage source 201 in the sensor circuit 20 to be provided.

Referring to 5 Now, an embodiment of an input device according to the invention will be described in more detail.

The (not shown) carrier is designed in this case to design a rotary knob. It is an annular first measuring electrode 14 provided, which on its side facing the user with an electrical insulation 26 For example, is provided of an elastomer.

Concentric to this first measuring electrode 14 is an arrangement of four second measuring electrodes in this case 16a . 16b intended. The second measuring electrodes 16a . 16b are each formed in a circular segment and together form a circular measuring electrode arrangement. The first measuring electrode 14 closes this measuring electrode arrangement 16a . 16b one.

The second measuring electrodes 16a . 16b are from the first measuring electrode 14 through insulation 18c spaced, which may be configured for example as a simple air gap or of a flexible elastomer. In addition, the four second measuring electrodes 16a . 16b to each other by further insulation 18b electrically isolated from each other.

In the non-actuated initial state of the input device is the first measuring electrode 14 at a first electrical potential, lie the two second measuring electrodes 16a at a second electrical potential, and are the two second measuring electrodes 16b on a third electric potential. The second measuring electrodes 16a . 16b with different potentials are arranged alternately to each other.

When a user presses the knob from outside (essentially radial pressure load), the outer insulation becomes 26 and the first measuring electrode 14 pressed radially inward in this area. This reduces the distance between the first measuring electrode 14 and the respective opposite second measuring electrode 16a . 16b so that the variable resistance 203 correspondingly reduced between these measuring electrodes. An induced potential equalization between these measuring electrodes is caused by the sensor circuit 20 recognized.

The more second measuring electrodes 16a . 16b are provided, the more accurate the angle detection in the operation of the knob.

If, in addition to such an angle detection, a rotational actuation of the rotary knob can also be detected, for example the second measuring electrodes can be detected 16a . 16b stationary on the carrier 12 be attached while the first measuring electrode 14 with the insulation 26 is rotatable about the second measuring electrode assembly around. If a pressing force is applied from the outside when the rotary knob is actuated, the distance between the first and second measuring electrodes is reduced 14 . 16a . 16b in one area. When turning the knob and thus the first measuring electrode 14 the position of this smaller distance between the first and second measuring electrodes changes 14 . 16a . 16b what caused by the sensor circuit 20 can be recognized. The air gap 18c in this case serves as a kind of bearing or friction layer between the measuring electrodes.

Incidentally, this embodiment corresponds to the above examples of 1 to 4 ,

LIST OF REFERENCE NUMBERS

10

control panel

12

carrier

14

first measuring electrode (s)

14a

first measuring electrode (s)

14b

first measuring electrode (s)

16

second measuring electrode (s)

16a

second measuring electrode (s)

16b

second measuring electrode (s)

18

insulation

18a

insulation

18b

insulation

18c

insulation

20

evaluation

22a

first finger

22b

second finger

24

door

26

insulator

201

DC voltage source

202

solid resistance

203

variable resistance

204

Voltage meter, voltmeter

205

first switching elements

206

second switching elements

Claims (10)

An input device for a home electronic appliance, comprising: an electrically non-conductive support (12); and at least one first measuring electrode (14, 14a, 14b) of an electrically conductive material and at least one second measuring electrode (16, 16a, 16b) of an electrically conductive material, electrically isolated from each other (18, 18a, 18b, 18c) on the Carrier (12) are arranged, wherein the at least one first measuring electrode (14, 14a, 14b) and the at least one second measuring electrode (16, 16a, 16b) in the non-actuated initial state of the input device have different electrical potentials and by an operation of the input device electrically conductively connected to each other, characterized in that the at least one first measuring electrode (14) and the at least one second measuring electrode (16a, 16b) being electrically isolated from the user (26); the at least one first measuring electrode (14) is movable relative to the at least one second measuring electrode (16a, 16b) upon actuation of the input device; and a sensor circuit (20) for detecting a change in potential of the at least one first measuring electrode (14, 14a, 14b) and / or the at least one second measuring electrode (16, 16a, 16b) is provided. Input device after Claim 1 characterized in that the sensor circuit (20) comprises a voltage divider having a series connection of a fixed resistor (202) and a variable resistor (203), the variable resistor (203) having a resistance value variable by an operation of the input device. Input device after Claim 1 or 2 , characterized in that at least two first measuring electrodes (14, 14a, 14b) and / or at least two second measuring electrodes (16, 16a, 16b) are provided. Input device after Claim 3 , characterized in that the sensor circuit (20) is designed to detect potential changes to a plurality of pairs of one of the first measuring electrodes (14, 14a, 14b) and one of the second measuring electrodes (16, 16a, 16b) in succession or in parallel. Input device according to one of the preceding claims, characterized in that upon actuation of the input device, a distance between the at least one first measuring electrode (14) and the at least one second measuring electrode (16a, 16b) is variable. Input device according to one of the preceding claims, characterized in that at least two second measuring electrodes (16a, 16b) are provided; and a first measuring electrode (14) designed annular and the at least two second measuring electrodes (16a, 16b) is arranged to encircle. Input device after Claim 6 , characterized in that the one first measuring electrode (14) is rotatable relative to the at least two second measuring electrodes (16a, 16b) in the circumferential direction. Input device according to one of Claims 1 to 7 , characterized in that the at least one first measuring electrode (14) and / or the at least one second measuring electrode (16) are arranged one behind the other along a circle or a circular arc. Input device according to one of Claims 1 to 7 , characterized in that the at least one first measuring electrode (14a, 14b) and / or the at least one second measuring electrode (16a, 16b) are arranged substantially in a straight line one behind the other. Electronic household appliance with at least one input device according to one of the preceding claims.

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