WO2005059935A2

WO2005059935A2 - Operator control

Info

Publication number: WO2005059935A2
Application number: PCT/EP2004/014331
Authority: WO
Inventors: Lutz Ose
Original assignee: E.G.O. Elektro-Gerätebau GmbH
Priority date: 2003-12-17
Filing date: 2004-12-16
Publication date: 2005-06-30
Also published as: DE10361350A1; EP1695035A2; WO2005059935A3

Abstract

The invention relates to an operator control (311) for e.g. an electric household appliance. Said control comprises a cover (317), which is extremely thin and flexible in one region (317a). A sensor element (315) is situated underneath the cover, said element consisting of a special plastic material, which is compressed when pressure is exerted on the thin region (317a), alters its volume and emits an electric signal during said volume alteration. Preferably, the material is an electrically charged polymer foam containing PTFE. The electric signal is evaluated as the operating pressure.

Description

Description of control device

Field of application and state of the art

The invention relates to an operating device for an electrical device according to the preamble of claim 1.

For example, it is known from EP-A 859 467 to create a capacitive touch switch with a sensor element made of porous, electrically conductive plastic. This sensor element rests on the underside of a glass ceramic surface. If a finger is placed on the glass ceramic surface above the sensor element, the capacitance of the sensor element changes, which can be evaluated as operation.

So-called membrane keyboards are also known. These work on the principle of an electrical contact, with one contact on a base plate and another contact on the inside of a slightly curved film. By lightly pressing the film, the two contacts are moved towards each other and the switch is closed. However, there is the problem that such electrical contacts are often subject to corrosion. In continuous operation, there is a risk that the contacts will deteriorate and at some point an operating device will no longer work.

Task and solution

The invention has for its object to provide an operating device mentioned at the beginning with which the disadvantages of the prior art can be avoided and in particular an operating device. direction or a switch can be created, the evaluation of which is as prone to failure as possible and whose function and safety is guaranteed for a very long time.

This object is achieved 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 are explained in more detail below. The wording of the claims is made the content of the description by express reference.

It is provided according to the invention that the operation takes place by pressing on a shape-changing or elastic operating area. This operating area has a sensor element or a sensor element is assigned to it, with the sensor element being pressed for operation. This press is evaluated as an operation. The sensor element consists of a plastic material which is porous or foam-like and which emits an electrical signal when the volume changes. By pressing, the volume of the sensor element changes, so that the pressing can be converted more or less directly into an electrical signal. In this way, electrical contacts, which are closed during operation as with a switch, can be avoided. Furthermore, a different functional principle is used than for sensor elements which change electrical properties, such as their electrical resistance, due to pressure and the resulting change in volume. Such sensor elements are to be regarded as purely passive sensor elements, a sensor element according to the invention being a type of electromechanical transducer. It should be noted, however, that only the conversion of pressure into an electrical signal is used. The plastic material is advantageously a cellular polymer, although it can also be a polymer foam. As a foamed material, it also contains pores or is similar to porous. In particular, such a polymer can contain PTFE or it can consist entirely of it. If such a plastic material is electrically charged, plus poles and minus poles, which lie opposite one another, form in the pore walls. By pressing, the pore walls and thus the plus and minus poles come closer, whereupon an electrical signal is emitted. This electrical signal can be processed with a corresponding evaluation, for example also with a signal amplification, and recognized as an operator control and passed on to a controller or the like.

The plastic material can be manufactured in a flat form or as a flat material. For this purpose, it can be stretched, preferably biaxially stretched.

Furthermore, it is possible to design a sensor element approximately in block form. In the direction of its greatest extent it can be several times as large as in the direction of its smallest extent. In this way, a certain cuboid shape with dimensions in the range of a few cm can be obtained.

As an alternative to a block-like sensor element, it can be designed as a thin flat material. The thickness can be less than one millimeter, preferably even less than 100 μm. Widths or lengths can be in the range of a few mm or cm.

Such a sensor element is advantageously contacted via one or more contact surfaces, which should be highly electrically conductive and can be, for example, metal in the form of a thin layer or foil. These contact areas are advantageously only to the sensor element without penetrating it. In this way, thin sensor elements can also be implemented and contacted. Two spaced surfaces can advantageously be provided as contact points, which are arranged in particular on opposite points or sides of the sensor element. The contact points are advantageously connected to a charging device for the sensor element. The sensor element can thus be recharged at certain time intervals or after a certain number of operations.

Furthermore, the plastic material advantageously has piezoelectric properties. A piezoelectric coefficient is advantageously in the range from 100 to 1000 pC / N. These properties can be somewhat reversible or have hysteresis loops similar to those of ferroelectric materials. One of the advantages of such plastic materials compared to piezoceramics is that they are more elastic and can therefore be used more easily and for other purposes.

There are several options for setting up an operating device. On the one hand, a sensor element can be freely accessible. It forms the operating area itself or an area of it. It can therefore be operated directly by pressing the sensor element, for example with a finger.

Alternatively, it is possible to arrange a sensor element under a cover, which is movable. As a result of this mobility, the operation is passed on to the sensor element in the form of pressing on, which in turn compresses it. Such a cover protects a sensor element from damage or wear. There are various options for forming a cover. On the one hand, it can be elastically movable, that is, in itself. For this purpose, it can be designed as an area of an operating panel that is thinner than its surroundings and can therefore be depressed to a limited extent. Alternatively, it is possible to design the cover or the operating area to be articulated and movable. This is also advantageous, for example, in applications with a higher pressure to be expected. A joint can also be designed as a film joint.

Furthermore, it is possible with an operating device to provide a sensor element with a recess or an opening. Illuminants can be arranged therein or project through or shine through, for example LEDs, and mark a location for the operation or the operating area. Here it is advantageous if a cover is provided above the sensor element, but it is translucent or transparent. Such lighting of the operating area can also transmit information to an operator in a pure marking for better meeting, for example about possible or successful operations.

In a further embodiment, it is possible for an operating device to have a plurality of operating areas which are provided for different operations or advantageously different functions. For example, the aforementioned sensor elements or touch switches can be replaced. In one embodiment of the invention, it is possible to provide separate sensor elements, each with a separate plastic body, for individual operating areas. The sensor elements are not connected or separated from each other. So they don't influence each other.

In another embodiment of the invention, it is possible to have a common control for several operating areas with different functions. to provide the same material layer from the plastic material. This can be viewed as a type of common sensor element, which is, however, divided into several sensor element areas. One sensor element area is assigned to one operating area and forms a kind of separate sensor element. Thus, a one-piece sensor element mat or the like can be provided for several operating areas, which is easier to handle during manufacture and assembly.

If several sensor element areas are provided on a single part, it is advantageous to separate them from one another by means of recesses and incisions or material dilutions. These material dilutions are particularly advantageously provided on the side facing the operating area. In this way, pressure that is exerted on one sensor element area is not transferred to adjacent areas.

For visual reasons, an operating area can be decorated or have a decor or a print. A so-called tactile structure is also possible, which results in a special sensation when touched. In the case of an operating device with a plurality of operating areas, it is possible to design each of them differently on their upper side, so that they can be easily distinguished from one another. It is even possible to print the top of a sensor element yourself or to provide it with a specific structure, even if no cover is provided over it.

In addition to the claims, these and further features also emerge from the description and the drawings, the individual features being realized individually and in groups in the form of sub-combinations in one embodiment of the invention and in other fields, and being advantageous and Protectable versions can be represented for which protection is claimed here becomes. The division of the application into individual sections and sub-headings do not limit the general validity of the statements made under these.

Brief description of the drawings

Embodiments of the invention are shown schematically in the drawings and are explained in more detail below. The drawings show:

Fig. 1 different side sections through control devices, to 6, wherein the sensor element is partly above and partly under a cover and partially protrudes. Detailed description of the exemplary embodiments

1 shows a side version of a first version of an operating device 1 according to the invention. It has an operating area 13, which is formed by a thin sensor element 15 on a cover 17. While the thin sensor element has a thickness of 1 mm, for example, and is elastic due to the material properties of the porous or foam-like material, the cover 17 underneath can be several millimeters thick and, above all, be essentially rigid or non-compliant. For example, it can be a so-called control panel of an electrical household appliance, for example a hob, an oven, a dishwasher or a clothes dryer.

Under the sensor element 15 there is a connection contact 19 on the left on the cover 17 and a connection contact 20 on the right, each in the form of a flat contact field with a connected conductor. This conductor can be routed to a controller, not shown, which a possible actuation of the sensor element 15 registered. This is described below. The sensor element can also be recharged in this way, as described above.

FIG. 2 shows, as a modification of FIG. 1, an operating device 111, in which a sensor element 115 is in turn arranged on a cover 117 and thus forms an operating area 11. The only electrical connection contact 119 is passed through an opening 121 through the cover 117 and runs, for example, to a corresponding control. So here the electrical connection runs through the cover. The area of the connection contact 119 is approximately as large as the entire sensor element 115, but this is only one possibility.

FIG. 3 shows an operating device 211 which has a cover 217 and an operating area 213. The operating area 213 is provided on the top of a thinner area 217a of the cover. Beneath this thinner area 217a, which is formed by a recess 221 underneath, is a sensor element 215, which is very thin, similar to the previous figures, for example a few 100 μm. The sensor element 215 rests on the underside of the thin region 217a and at the same time rests on a base plate 218. While the thinner area 217a can be pressed down by light finger pressure and thus exerts pressure on the sensor element 215, the base plate 218 is rigid, stationary and immovable. The contact is made via the two contacts 219 and 220. These are similar to those described above. The base plate 218 has an opening 222. A breakthrough 223 is provided in the sensor element 215 in its upward extension. Another such breakthrough can be in the cover 217 or in the thin region 217a. Alternatively, the thin region 217a can be designed to be translucent, so that light can pass through the LED 225 arranged under the base plate 218 and shining through the openings. In this way, an operator can be shown where the operating area 213 is located. Furthermore, information can be displayed, for example in the form of a symbol or by a special, for example flashing, type of display.

Instead of LED 225, glow lamps can also be provided, as well as seven-segment displays for larger breakthroughs. Here it is also conceivable to make the base plate 218 and cover 217 or thin region 217a more translucent and to cut out the sensor element 215 only in the region of the segments of the seven-segment display.

FIG. 4 shows a modification of FIG. 3. An operating device 311 in turn has a cover 317, a recess 321 being provided. This is covered at the top by a thin area 317a. This is, for example, rectangular and connected to the rest of the cover 317 on one side, pointing to the left in FIG. 4, via a type of film hinge 317b. The film hinge 317b can also be designed as an area that can be made even thinner than the thin area 317a for greater mobility. It is functionally essential that the thin area 317a is movable in the area of the film hinge 317b or an alternative means. This forms the operating area 313 and passes an operating pressure on to the sensor element 315 through an operator's finger 330. This in turn is pressed against a base plate 318 and thus outputs the electrical signal corresponding to the change in volume via a right-hand connection contact 320, which is arranged under the sensor element 315. at In such an arrangement, it is recommended for better mobility to cut out the contours of the thin region 317a to the film hinge 317b or to provide it with a slight gap. The left connection contact 319 rests on the top of the sensor element 315. Thus, the sensor element is located between the two connection contacts 319, 320, and it can be recharged in order to then release this charge by pressing as an operator.

5 shows a further operating device 411, in which a sensor element 415 extends through a cover 417 from below. For this purpose, an opening 421 is provided in the cover 417. The sensor element 415 protrudes through it, which is arranged on a rigid and immovable base plate 418 and is designed to be electrically contactable with the connection contacts 419 and 420. The opening 421 can either be slightly larger than the sensor element 415 and the base plate 418, so that a thin gap is present. Alternatively, a fit that is as precise as possible can be provided. According to a further possibility, the sensor element 415 can overlap the base plate 418, which is only slightly smaller than the opening 421, on all sides. If the base plate 418 is then introduced into the opening 421, the sensor element 415 stretches over it, so to speak, and on the one hand lies taut on the base plate 418. Furthermore, the opening 421 is sealed at the bottom.

On the top of the sensor element 415, where the operating area 413 is formed, this carries a print 427. This print 427 can show information for an operator, for example with regard to a function that can be triggered by the operation at this point. The printing 427 can be applied in different ways, which also depends on the design of the sensor element 415 or the corresponding plastic material. The need The cover can also be a sticker, for example, or a light structure that can be seen or felt.

FIG. 6 shows an operating device 511 in which a sensor element 515 is block-like with a thickness that goes considerably beyond that of the sensor elements in the other figures and is in particular a few millimeters, for example 10 to 15 mm. Through an opening 521 in the cover 517, the sensor element 515 projects upwards and rises far above the cover. In this way, an operating area 513 can be created which is considerably higher than the cover 516 and which is, so to speak, very exposed. Otherwise, the sensor element 515 rests on a rigid base plate 518 with electrical connection contacts 519 and 520. Function

The basic function of the sensor elements 15 to 515 is the same for all operating devices 11 to 511. If, for example, pressure is exerted on the operating area 13 to 513 by applying a finger 330, an electrical signal is generated in the plastic material of the sensor elements due to the special properties mentioned at the beginning. This can be recorded via a control device or an evaluation. The strength of the electrical signal depends on the strength of the pressure or the change in volume of the sensor element due to the pressure, the special material properties, the thickness of the sensor element and possibly the previous charging of the sensor element. A response threshold can thus be set using these factors. For some applications, it may be necessary to recharge the sensor element electrically from time to time. For this purpose, there may be a second one in addition to the electrical connection contact shown in each case distant, preferably opposite, connection contact provided, charging should not be possible via the connection contacts used for detection. Appropriate control means that charging can take place either after each operation, at regular intervals or depending on the strength of the measured signal.

Claims

claims

1. Operating device for an electrical appliance, preferably a household appliance, the operation being carried out by pressing a shape-changing or elastic operating area (13, 113, 213, 313, 413, 513) with a sensor element (15, 115, 215, 315, 415 , 515), wherein the pressure acts on the sensor element and is evaluated as an operation, characterized in that the sensor element consists of plastic material and changes its volume by pressing, the plastic material being porous or foam-like and changing in volume emits electrical signal.

2. Control device according to claim 1, characterized in that the plastic material is a cellular polymer or a polymer foam, in particular containing PTFE, wherein the plastic material is electrically charged and the plus and minus poles in the pore walls by pressing each other approach and emit an electrical signal.

3. Control device according to claim 1 or 2, characterized in that the sensor element (15, 115, 215, 315, 415) is made as a flat material and is preferably biaxially stretched.

4. Control device according to one of the preceding claims, characterized in that the sensor element (15, 115, 215, 315, 415) is a thin flat material, in particular with a thickness of less than 1 mm, preferably less than 100 microns.

5. Control device according to claim 1 or 2, characterized in that the sensor element (515) is block-like, wherein it preferably in the direction of its greatest dimension is a maximum of four times as large as in the direction of its smallest dimension and in particular has a cuboid shape.

6. Operating device according to one of the preceding claims, characterized in that the sensor element (15, 115, 215, 315, 415, 515) is contacted by means of at least one electrically conductive surface, in particular via adjoining contacts (19, 20, 1 19, 219 , 220, 319, 320, 419, 420, 519, 520).

7. Control device according to claim 6, characterized in that two spaced surfaces (19, 20, 219, 220, 319, 320, 419, 420, 519, 520) are provided as contact points, in particular at opposite points or sides of the sensor element ( 15, 115, 215, 315, 415, 515) are arranged, the contact points being connected to a charging device for the sensor element.

8. Control device according to one of the preceding claims, characterized in that the plastic material has piezoelectric properties, preferably with a piezoelectric coefficient in the range of 100 to 1000 pC / N.

9. Operating device according to one of the preceding claims, characterized in that the sensor element (15, 115, 415, 515) is freely accessible and itself forms the operating area (13, 113, 413, 513) or a surface of the operating area forms.

10. Control device according to one of claims 1 to 8, characterized by a movable cover (217, 317), under which the sensor element (215, 315) abuts, the cover transfers the pressure to the sensor element by the movement and compresses it.

1 1. Operating device according to claim 10, characterized in that the cover (217) is elastically movable, wherein it is preferably a thinner area of an operating panel (11) than in its environment.

12. Operating device according to claim 10, characterized in that the cover (317) is articulated.

13. Control device according to one of the preceding claims, characterized in that the sensor element (215) has a recess or an opening (222) and is preferably a voluminous body, the recess or the opening approximately in the direction of the operating area (213), wherein illuminants (225) are arranged therein and preferably a separate cover (217) above the sensor element is translucent.

14. Operating device according to one of the preceding claims, characterized by a plurality of operating areas (13, 113, 213, 313, 413, 513) for different operations or functions.

15. Operating device according to claim 14, characterized in that for individual operating areas (13, 113, 213, 313, 413, 513) separate sensor elements (15, 115, 215, 315, 415, 515) are provided with a plastic body are, the individual sensor elements or plastic bodies are separated or spaced apart.

16. Operating device according to one of claims 1 to 14, characterized in that for several operating areas (13, 113, 213, 313, 413, 513) a common sensor element or a common plastic body is provided, which is divided into a plurality of sensor element areas, one sensor element area being assigned to or forming an operating area.

17. Operating device according to claim 16, characterized in that the sensor element areas are separated from one another by recesses and notches, preferably the recesses or notches on the side facing the operating area (13, 113, 213, 313, 413, 513) are provided.

18. Operating device according to one of the preceding claims, characterized in that an operating area (13, 113, 213, 313, 413, 513) has a decor or a print (427) or a tactile structure, preferably in the case of an operating device ( 11) with several operating areas, the operating areas on the top are designed differently.