DE10352681A1 - Operating device for operating an electrical appliance with a touch switch - Google Patents

Abstract

In one embodiment of the invention, an operating device (11) for, for example, a tumble dryer can be provided which has a touch switch together with a sensor element (17). The sensor element (17) is a suitably formed foam body. This is located on a contact surface (13) and forms a capacitive Ankoppelmöglichkeit for example, the touch by a finger (15). The sensor element (17) bears against a printed circuit board (21) and has a central longitudinal channel (18) in which an LED (23) is seated on the printed circuit board. To avoid electrical interference, a signal-to-noise ratio between sensor element (17) and LED (23) and supply lines (24) is maintained in that the sensor element is at a distance from other electrical devices or corresponding recesses in the area where it is otherwise too close would.

Description

field of use and state of the art

The The invention relates to an operating device for operating an electrical appliance, which for example, a household appliance like a tumble dryer can be, according to the generic term of claim 1.

Operating devices or so-called touch or touch switches are for example from the EP 859 467 A1 known. These usually work well, but have a compact design, the problem that they can have a certain susceptibility to interference. This limits above all the freedom in the design, in particular with regard to the electrical controls. So it is for example from the above EP 859 467 A1 known to provide the body of the sensor element with a through hole in which an LED is mounted. This can radiate upward through a cover or front panel, in particular a glass ceramic cover or from plastic, to identify the sensor element or the contact point formed thereby. Here, however, often the problem arises that the control of the LED interferes with the evaluation of the sensor element.

From the EP 1 257 057 A1 a similar control device is known. Here, too, below a touch surface, illumination is provided, inter alia, as a marking of the contact surface.

From the EP 1 030 536 A1 It is known to provide a capacitive touch switch in a control device for a hob near or above a display.

From the DE 3119495 A1 It is known to mount a thin foam layer as a sensor for a capacitive proximity switch on a raised angled support. The foam layer serves to adapt to the underside of a cover.

Task and solution

Of the Invention is based on the object, an aforementioned operating device to create, with which the problems of the state of the art avoided can be and in particular an operating device or an arrangement of a Sensor element can be created, which at different possible arrangements an interference immunity guaranteed.

Is solved This object by an operating device with the features of Claim 1. Advantageous and preferred embodiments of the invention are the subject of the further claims and will become hereafter explained in more detail. Of the Wording of the claims is thereby by explicit reference to the content of the description.

According to the invention is at a control device mentioned above, the sensor element is a flexible and more electrically conductive Body. It is arranged adjacent to a cover with one side, wherein it forms in a known manner thereby an area of a capacitor, its capacity by approach or touch variable, what can be evaluated. The cover serves as a touch or Approach surface. The sensor element is arranged or attached to a support, which with electrical Ladders, especially for the sensor element itself, can be provided. This edition can in particular, be a printed circuit board. The body of the sensor element has while a minimum distance or signal to noise ratio to the electrical Ladders or on the pad, which is usually at least one to several millimeters. This distance is intended to prevent electrical interference signals, originating in particular from the electrical lines on the support, in the Sensor element or its body be coupled and thus the signal of the sensor element or interfere with its evaluation can. If this distance is maintained, then, for example, LED provided very close to or in a recess in the sensor element be. For an increased immunity can the distance, which in the following also as signal to noise ratio is called, even 3-4 mm or more.

By training as a body For example, the sensor element may have electrical properties which it is mainly due to its volume or its length in the direction of the cover obtained. Here is above all an electrical resistance to call the damping of interfering signals can cause. This effect can be done with a thin layer of one Material can hardly be achieved. Here would be the resulting electrical Resistance too low.

In a further embodiment of the invention can be provided that the sensor element does not touch the support directly. The resulting result from the distance can be, for example, the signal to noise ratio. This is preferably achieved by a spacer element which is constructed, for example, in the manner of a bridge. At this over the support rising spacer element, the sensor element can be arranged or attached. The bridge or the spacer element can also be used for electrical con serve timing.

is the spacer as a bridge trained, it can be one or more armed. So you can the bridge several sensor elements may be arranged side by side. In this Case would have one electrical contacting to the sensor elements independent of the bridge be formed, for example via additional connections.

Prefers it is envisaged that the bridge, at which the body the sensor element is applied, is soldered to the support. Alternatively, she can through an easily detachable Connection to be attached to the support, for example by a locking connection. This is how a bridge can be mechanically locked be, under certain circumstances even solved by hand again be needed without tools.

The Distance element is advantageous with a fixture or holder for the body Mistake. This can either be a gluing. Alternatively it is an attachment to a thorn or a similar projection possible to to attach the sensor element to the spacer element.

alternative can the body of the sensor element at least partially rest on the support. Then are either all electrical conductors or electrical components with at least the Signal to noise ratio too to provide the sensor element. Furthermore, it can be provided that the sensor element of the other course of its geometric Deviating form at appropriate or endangered place a recess or Has indentation, so in turn to produce the signal to noise ratio.

at a preferred embodiment of Invention comprises the sensor element or body, which is substantially is formed of a solid material, in a central area a recess on. This can be used as a central, continuous bore to run in the direction of the contact surface. While the sensor element with one side of the body at the bottom of the Cover or contact surface is present, At the other end a light source is arranged. radiated Light goes through the body towards the bottom of the contact surface. This should be for the lighting have a translucent light channel or translucent at this point.

One such light channel can, for example, a fitted in the cover Be insert made of transparent or translucent material. He can For example, in the body or in the recess extend into it and run in the direction of the bulb, especially zoom up to the bulb.

Of others can the bulbs on the support, which in this case advantageous a printed circuit board is to be arranged. The electrical leads to the bulb can be provided on the side of the support, which to the sensor element points. In this case, it is possible on the bulb an attachment for to provide the sensor element, in particular by the lamp itself. This can for example be a correspondingly large or appropriately designed housing have, on which the sensor element are simply plugged can. In doing so, the body can the sensor element tightly and mechanically fixed to the light source be.

alternative to a mounting of a lamp directly in the sensor element It may be provided, light by means of a light guide in or to introduce to the sensor element, which is basically similar may be formed as previously described. A fundamental Advantage of such a light guide is that, so that bulbs, which usually because of the electrical control, the sensor element to disturb can, may be provided away from the sensor element. Furthermore it is possible to get one such light guide also form as a holder for the sensor element. For this he may, for example, have a corresponding widening, which engages under the sensor element. With another end can the light guide is inserted into a corresponding opening on the cover become. So is a translucent Closure of the cover achieved by means of which simultaneously the sensor element in exactly predetermined position at the bottom the cover is attached.

The Edition is advantageous a circuit board. It can be one-sided For example, with SMD components. The component side has advantageous to the contact surface, causing For example, light sources such as LEDs are used as SMD components can. It can also be equipped on the bottom or two sides.

In a further embodiment of the invention, it is possible to make the body of the sensor element so that it corresponds approximately to a truncated cone. This means that it is relatively small towards the contact point in order to contact the contact surface. At the opposite end, it is far-reaching and considerably larger, wherein the sensor element body advantageously has constant wall thickness. This has the advantage that at this larger end an LED can be arranged according to the previous description. Due to the large dimensions of the body at this end a sufficient distance between the sensor element and such an LED is ensured. In addition, it can be seen before that even with such a Sensorele ment body in the area in which, for example, the leads to the LED run, the sensor element is cut or excluded.

These and further features of preferred embodiments of the invention go out from the claims also from the description and the drawings, wherein the individual features each for alone or in the form of subcombinations an embodiment of the invention and in other fields be realized and advantageous also for protectable versions can represent for the protection is claimed here.

Summary the drawings

embodiments The invention are shown schematically in the drawings and will be closer in the following explained. In the drawings show:

1 a side section of a possible operating device according to the invention with a sensor element which is arranged on a bridge between the board together with the LED and the contact surface,

2 a modification of an operating device 1 with distance-maintaining spacer nails for the sensor element,

3 a modification of an operating device with a holder for the sensor element, which is designed as a transparent plastic part, which is slipped onto the LED,

4 a modification of an operating device, in which a frusto-conical sensor element is clamped between the board and the contact surface,

5 a plan view of the sensor element 4 and

6 a side view of the sensor element 4 ,

detailed Description of the embodiments

In 1 is schematically an operating device 11 shown what a cover 12 having a contact surface 13 on which a finger 15 is placed for operation, as can be seen by the dashed line. Below the contact surface 13 is a sensor element 17 provided, which at the bottom of the cover 12 enough. At the other end is the sensor element 17 at a bridge 19 created, which on a circuit board 21 is attached and runs over this. The sensor element may have a height of several mm, for example 10 mm or more. Thus, in conjunction with the specific electrical resistance of the material, a total resistance is achieved, which can dampen disturbances, for example.

As can be seen, the sensor element has 17 a central longitudinal channel 18 on, in the light from one below the sensor element 17 arranged LED 23 is blasted upwards and through a translucent insert 25 in the cover 12 is blasted upwards. Such a translucent insert 25 is then to use when the cover 12 in itself or in the area of the contact surface 13 is not translucent.

The formation of the sensor element 17 made of electrically conductive plastic or foam and its functional principle, in particular because of the electrical properties of the formation as a voluminous body, can from the EP 859 467 A1 The contents of this document are hereby incorporated by express reference into the content of this description.

The LED 23 is with schematically illustrated supply lines 24 provided, which in the case in this case one-sided printed circuit board 21 on the cover 12 are provided facing side. Through the bridge 19 , which also with a supply line 20 for electrically contacting the sensor element 17 is provided, the sensor element is at a distance from the LED 23 as well as the supply lines 24 held. This distance, which is about 2 mm at the scale 1: 2 of the representation selected here, is the aforementioned signal-to-noise ratio. By observing this signal to noise ratio is a coupling of the LED 23 for presentation given signals in the sensor element 17 or their supply lines 20 across the bridge 19 prevented. In this respect, it is also important that not only the sensor element 17 itself, but also its electrical contacting the signal to noise ratio to other electrical components, such as the LED 23 , adheres. This is from the 1 to see. There are also the leads 20 to the bridge 19 over which the sensor element 17 contacted, in a different direction than the supply lines 24 the LED 23 ,

By the in 1 As shown, it is possible to use the LED 23 form as a so-called SMD component and thus the supply lines 24 to on the to the touch area 23 provide facing side. Thus, the circuit board can be fitted on one side, to the cover 12 pointing out. Alternatively, it is also conceivable, the supply lines 24 to the LED 23 or other leads to other components on the circuit board 21 on the of the sensor element 17 or the contact surface 13 abge provided side turned. In this case, the signal-to-noise ratio according to the invention can nevertheless be provided for the sensor element, for example by means of an illustrated bridge, in order to further increase the interference immunity.

From the modification in 2 is the same structure of the cover 12 to recognize how the bridge 19 by so-called spacer nails 127 is replaced. These may be in the nature of solder pins or the like on the circuit board 121 be attached. On the upper peaks is the sensor element 117 which is similar to 1 is formed, plugged.

The electrical contact to the sensor element 117 can be beneficial over the spacer nails 127 take place, which may be formed of metal and, for example, on the circuit board 121 can be soldered. The circuit board 121 is equipped here on both sides, as can be seen.

In the further embodiment according to 3 is on the LED 223 which are similar to 1 with supply lines 224 on the circuit board 221 is provided, a holder 229 attached or attached. The holder 229 is made of transparent material, especially clear plastic. This is illustrated by the fact that the light of the LED 223 through the holder 229 passes. Outwardly projecting points the holder 229 protruding approaches or a circumferential collar 230 on. This holds the sensor element 217 at a distance to the LED 223 or the circuit board 221 , similar to the bridge before 1 or the spacer nails according to 2 , The fastening of the bracket 229 on the LED 223 may advantageously be such that it is self-locking and thus stable without further compounds, such as gluing or the like. In one embodiment, not shown, the holder may project upwardly with a portion corresponding to the insert 25 out 1 similar. This section could be mounted in the cover so that it fixes the holder and sensor element to the cover. A support on the circuit board or the LED would then no longer necessary and the sensor element without a circuit board or the like. be held by the holder in a defined position on the cover.

The electrical contact to the sensor element 217 takes place by a schematically indicated supply line 231 , This can be, for example, a wire which is inserted into the sensor element. Likewise, it could be a contact spring which is pressed laterally against the sensor element.

In 4 is a further embodiment of an operating device 311 shown. Here, on the one hand, the cover 312 only an opening through which light emerges. Furthermore, the sensor element 317 frusto-conical shape with a substantially constant wall thickness. The signal-to-noise ratio according to the invention is achieved here in two different ways. In the left half of the sensor element 317 its wall extends through the obliquely inclined course of the upper contact surface 313 far from the LED 323 as well as the left supply line 324 away, that the signal to noise ratio is guaranteed. The left supply line runs 324 for example, with the corresponding signal to noise ratio to the sensor element 217 to a connection, not shown, on the circuit board 321 , which leads to the bottom and leads away, for example, with a cable. Thus, in any case always the required signal to noise ratio is guaranteed.

In the right area of the sensor element 317 is a section 332 provided in the manner of a partial perforation. Through this section 332 runs the right supply line 324 outwards on the circuit board 321 along. The underlying technical principle is that the sensor element 317 essentially on the circuit board 321 rests and only in those areas where it is the LED 323 or a supply line could come close, a corresponding cutout or a recess are provided.

This cutout could also, what is not shown, approach from the outside a light guide to the sensor element and go inwards into the sensor element, similar to the transparent holder in 3 , Thus, a distance between the sensor element and light sources or supply lines can be created. The light guide may also have a supporting function for the sensor element.

In the 5 and 6 is shown in plan view and in uncut side view, as the cutouts 332 through the wall of the sensor element 317 to lead. It can be seen how the cutouts 332 are provided approximately opposite. However, it is also conceivable to carry them out relatively close to one another or to guide a plurality of electrical lines or feed lines through a single slightly wider cut-out.

Claims (15)

Control device ( 11 ) for operating an electrical appliance, preferably a household appliance such as a tumble dryer, with a sensor element ( 17 ) of a proximity or touch switch, wherein the sensor element is a flexible, electrically conductive body which is attached to a cover ( 12 ) is arranged as a contact surface, wherein the sensor element ( 17 ) at one with electrical conductors ( 20 . 24 ) provided pad such as a ladder plate ( 21 ) is arranged, characterized in that the body of the sensor element as the signal to noise ratio at a distance from the electrical conductors ( 24 ) or a distance to the overlay ( 21 ), wherein the distance is at least one to two millimeters. Operating device according to claim 1, characterized that the distance is at least three millimeters, preferably at least four millimeters. Operating device according to claim 1 or 2, characterized in that the sensor element ( 17 ) the edition ( 21 ) not touched directly. Operating device according to claim 3, characterized in that on the support a spacer element ( 19 . 127 . 229 ), preferably a bridge ( 19 ), on which the sensor element ( 17 ) several millimeters away from the support ( 21 ) is arranged or fastened, wherein in particular on the spacer element to the sensor element towards a fastening is provided, preferably a bonding or mechanical plugging. Operating device according to claim 4, characterized in that the spacer element ( 19 . 127 . 229 ) for the signal-to-noise ratio to the electrical supply lines ( 24 ) on the edition ( 21 ) is soldered, wherein preferably the spacer element, the electrical connection to the sensor element ( 17 ). Operating device according to one of the preceding claims, characterized in that the support is a single-sided printed circuit board ( 21 ), wherein preferably the component side to the contact surface ( 13 ) points. Operating device according to claim 1 or 2, characterized in that the sensor element ( 17 ) partly on the edition ( 21 ) and in the area in which on the support electrical conductors ( 24 ) or electrical components ( 23 ) are arranged, the sensor element at least one correspondingly large recess ( 332 ) to comply with the distance. Operating device according to one of the preceding claims, characterized in that the sensor element ( 17 ) has the shape of a hollow truncated cone, wherein it is at the contact surface ( 13 ) side facing a continuous surface covered to rest against the underside of the contact surface ( 13 ). Operating device according to one of the preceding claims, characterized in that the sensor element ( 17 ) has a recess in a central region, preferably a bore ( 18 ) in the direction of the contact surface ( 13 ) too. Operating device according to one of the preceding claims, characterized in that at the end of the body of the sensor element ( 17 ), which depends on the contact area ( 13 ) away, a light source is arranged, in particular an LED ( 23 ), and its light through the body or through a recess ( 18 ) radiates in the body of the sensor element to the contact surface, wherein preferably the cover ( 12 ) a translucent light channel ( 25 ) having. Operating device according to claim 10, characterized in that the light-transmitting light channel ( 25 ) an insert of transparent material in the cover ( 12 ), wherein it preferably extends at least partially into the body and in particular up to the light source ( 23 ) runs out. Operating device according to claim 10 or 11, characterized in that the lighting means ( 23 ) on the edition ( 21 ), in particular in the form of a printed circuit board, wherein preferably the supply lines ( 24 ) to the light source at the to the sensor element ( 17 ) side facing the support are provided. Operating device according to one of claims 10 to 12, characterized in that on the lighting means ( 23 ) directly a fastening for the body of the sensor element ( 17 ) is provided, preferably an enlarged housing ( 229 ) of the luminous means, to which the body of the sensor element with a corresponding recess ( 218 ) is tightly and mechanically halternd fastened. Operating device according to one of the preceding claims, characterized in that light guides are provided which are remote from the sensor element ( 17 ) arranged bulbs as far as the sensor element or in this Chen Chen and radiate through a recess of the body up to the cover. Operating device according to one of the preceding claims, characterized in that a light guide at one end a holder for the body of the sensor element ( 17 ), in particular a broadening, and at the other end by a recess in the contact surface ( 13 ) can be plugged, as a light guide and attachment for the sensor element.