WO2009023888A2

WO2009023888A2 - Pressure-sensitive coordinate measuring device

Info

Publication number: WO2009023888A2
Application number: PCT/AT2008/000294
Authority: WO
Inventors: Andreas Tanda; Marjanovic Nenad; Alberto Montaigne
Original assignee: Plastic Electronic Gmbh
Priority date: 2007-08-21
Filing date: 2008-08-21
Publication date: 2009-02-26
Also published as: AT506111A2; WO2009023888A3

Abstract

The invention relates to a pressure-sensitive coordinate measuring device (1) comprising at least one elastically restorably deformable carrier layer (2) and at least one first (3) and second (4) electrode arrangement, which are arranged on the first (5) or (6) flat side of the carrier layer (2), wherein the first electrode arrangement (3) is formed by at least two electrodes (8) and the second electrode arrangement (4) is formed by at least one electrode (9), wherein the carrier layer (2) is made of a polymer foam and an evaluation device (21) for measuring the electric characteristics of the electrodes (8) of the first electrode arrangement (3) and for measuring the electric characteristics of the electrodes (8, 9) of the first (3) and second (4) electrode arrangement is provided. The invention further relates to a method for determining the position and intensity of a force application on a pressure-sensitive coordinate measuring device (1), wherein a force application on the polymer foam brings about a change of the electrical properties of the foam.

Description

Dracksensitive coordinate measuring device

The invention relates to a pressure-sensitive coordinate measuring machine comprising at least one carrier layer and at least one first and second electrode arrangement, wherein the carrier layer is formed from an elastically recoverable deformable material and has two flat sides, which are arranged substantially parallel to each other and are spaced apart by the thickness of the layer , and wherein the first electrode arrangement is formed by at least two electrically insulated electrodes and is arranged on the first flat side of the carrier layer and wherein the second electrode arrangement is formed by at least one electrode, and is arranged on the second flat side of the carrier layer. The invention further relates to a method for determining the position and intensity of a force on a pressure-sensitive coordinate measuring machine wherein a force on the polymer foam causes a change in the electrical properties of the foam.

To determine the position of the contact point of an object with a planar carrier layer, the skilled person has several options. For example, switching elements can be arranged in or on the carrier layer which close a contact with a force acting on the carrier layer and thus on the basis of the knowledge of the position of the closed contact, the position of the acting force can be determined directly. This method uses mechanical switching elements, which is disadvantageous in terms of a long, trouble-free and maintenance-free as possible operation of the position detection device. Another disadvantage is that such devices usually require a significantly higher manufacturing costs, since mechanical switching elements are usually constructed complex or consist of a plurality of parts and thus difficult to manufacture automated. A further problem is when special encapsulation of the position detection device is required in order to use the device in certain environments that require increased protection, for example, in a chemically aggressive environment or in an ex-environment. Therefore, preference should be given to those devices for determining the position of an acting force, which manage without moving parts.

Contactless and as far as possible without moving parts, optical methods for determining the position of a force. In this case, light-emitting and light-receiving devices are arranged in the edge regions of the portion of the carrier layer, the position detection takes place here by raster-like querying of the contact surface by the light receiving device. Other non-contact methods use, for example, electromagnetic waves or sound waves, in particular ultrasound, where the position of a force can be calculated from the detected wave pattern.

Another method uses the mechanical effects of a force on a position-determining material. A force on a material leads to microscopic changes in the material tension inside the material. Especially in transparent or semi-transparent materials, these voltages can be visualized by illuminating with a light of a characteristic design. In another method, these voltage lines are recorded by an image capture device and the position of the applied force is determined by an evaluation device.

CA 2 355 434 A1 discloses a coordinate field with which the position and strength of the applied force can be determined. The touchpad is formed by individual, discrete pressure-sensitive elements which are arranged between two cover plates. A force acting on a cover plate of the touch panel causes a local deformation in the underlying pressure-sensitive element, which results in a change in the electrical resistance of the pressure-sensitive element, wherein the change in the resistance is greater, the greater the force acting.

DE 103 04 704 A1 discloses a data input device which comprises a touch panel for position input, which is mounted so as to be tiltable in a housing. The touchpad is held in its upper resting position by the rest position of several buttons. The position determination takes place by contact of an object with the touchpad. When the force on the touch pad is amplified, at least one of the buttons closes. By knowing the position of the closed switch, a function stored for this position can be activated. In order to make contact, the pressure point of a switch must be overcome; stepless force determination is not possible.

US 2007/0052691 A1 also discloses a touchpad with a plurality of underneath. Neten switches. The touchpad is in turn held by the rest position of the switch in its upper rest position and upon application of force one or more switch contacts are closed. By means of a suitable arrangement of the switches and corresponding evaluation of the individual contact inputs, it is possible to determine several force action positions.

Also, US 5,854,625 A discloses a similar arrangement, but instead of the switch, air capacitors are arranged. The cover layer is supported in a sturdy frame in such a way that a fixed distance between the two capacitor plates is ensured at rest. A force on the contact element thus leads to a change in the distance of the capacitor plates, which changes their capacity. From this capacity change, the strength of the applied force can be calculated.

The object of the invention is therefore to provide a Berührfeld with which in addition to the position of at least one acting force can also determine the strength of the applied force. The Berührfeld should be constructed without mechanically moving, in particular without contact components. A further object of the invention is to find a method with which the position and strength of at least one force acting on a touchpad can be determined at the same time.

The object of the invention is achieved inter alia by designing an evaluation device for measuring the electrical characteristics of the electrodes of the first electrode arrangement and for measuring the electrical characteristics of the electrodes of the first and second electrode arrangements. This has the very special advantage that at the same time at least one position in the plane of the first electrode arrangement and the strength of the force acting on this at least one position can be determined. In particular, with the measuring device according to the invention a determination of the position and force measurement without switching the electrodes or without a time offset between the two measurements possible.

Furthermore, the object of the invention is achieved in that the carrier layer is formed by a polymer foam. The electrical properties of such a foam can be influenced in an advantageous manner even after the production of the foam. There- By way of example, the sensitivity of the force measurement can be specifically adapted to the desired field of application.

With regard to a further embodiment of the device according to the invention as an input means that can be operated by a user, a design of the carrier layer has as one

Foam material, in particular as a polymer foam has the advantage that this gives the operator a retroactive effect through a sensation of pressure. In addition to the two-dimensional position input, which allows a direct feedback on the desired position input by moving an object over the contact surface eg. A finger, now also allows a tactile deformation of the foam material advantageously a subjective detection of the coordinate input in the third dimension.

According to advantageous developments, the polymer foam is closed-cell or open-celled or formed from a material from the group comprising polypropylene or polyethylene.

Polymer foams have the particular advantage that they are inexpensive and are environmentally friendly to produce and dispose of.

However, the polymer foam may also be extruded, for example, from a material of the group comprising ethylene copolymer, polyamide 6 (nylon 6), PVDF (Kynar (R)), ethylene vinyl acetate copolymer, polyurethane, expandable polystyrene EPS (Neopor (R)) Polystyrene XPS (Styrodur (R), Peripor (R)) or melamine resin (Basotect (R)), this list is not restrictive to read.

If the minimum capacitance of a capacitor which is formed by the electrodes of the first electrode arrangement or by the electrodes of the first and second electrode arrangement is greater than 4fF, even the smallest deformations, which cause a change in the capacitance, can be determined with known measuring methods for the determination of the capacity.

The electrodes of the first and / or second electrode arrangement can be applied directly to the flat sides of the carrier layer. Furthermore, there is the possibility that on the First and / or second flat side of the carrier layer, a separation layer is applied, wherein the first and / or second electrode assembly is subsequently applied to this separation layer.

This separation layer, whose thickness is preferably less than 50 .mu.m, may for example be designed to be electrically insulating, as a result of which the applied electrodes of the first and / or second electrode arrangement are electrically insulated from the underlying carrier layer. Furthermore, by means of the strength or rigidity of the separation layer, a bending stiffness of the coordinate measuring device can be realized in a targeted manner. This is of particular importance if, for example, it is to be expected that a high area of force can occur on a small surface area, for example a punctiform force attack, and this force effect could possibly damage the carrier layer. A correspondingly formed separation layer distributes the acting punctiform force over a larger section and thus relieves the underlying carrier layer.

Likewise, the electrodes of the first electrode arrangement and of the electric field of the electrodes of the first and second electrode arrangement can be formed by the separation layer for the purpose of selectively influencing the field of the electric field.

In an advantageous further embodiment, the separation layer can be designed such that it is suitable for the delivery or forwarding of electromagnetic radiation in the visible optical region. This allows, for example, realize a backlight of the keypad.

It is of decisive advantage if the electrodes are formed from polyethylene dioxythiophene (PE-DOT). This material is an electrically conductive polymer and thus belongs to the organic materials. With regard to the environmental aspect, organic materials have the significant advantage that both the production and the disposal brings only a low environmental impact. Furthermore, organic materials are mostly in an aggregate state, which brings significant advantages for the production. In particular, manufacturing methods or methods can be used that would not be possible with metallic conductors. For example, the electrodes can be applied to the flat side of the carrier layer or to the protective layer by means of a printing process. Furthermore, the electrodes can also be formed from polyaniline (PANI) or polystyrene sulfonate (PSS).

A decisive advantage is obtained when the electrodes are formed of a transparent conductive material. For example, transparent electrodes formed of indium-tin oxide (ITO) enable the coordinate measuring apparatus to be no longer directly recognizable to a user as the electrodes are no longer apparent.

Transparent electrodes also allow an unobstructed view of the separation layer or the flat side of the carrier layer. In further embodiments, it is for example possible that by means of the separation layer, a control panel is formed, for example. By imprinting on the separation layer, wherein the electrodes arranged thereon do not cover the elements of this panel and thus an unobstructed supervision of the control panel is possible.

If the electrodes are formed from a translucent metal layer, a particularly good current supply or discharge and contact with the separation layer or the flat side of the carrier layer is advantageously achieved. Such formed electrodes may be formed of a material selected from the group consisting of gold, silver, chromium, copper and aluminum.

For example, if the thickness of the electrodes is in the range of 3 nm to 1 μm, and is typically 100 nm, a usually non-transparent metal layer becomes translucent. This has the advantage that the portions of the separation layer or of the flat side of the carrier layer situated below the electrode shine through the electrode and, in addition, high electron conductivity of the metallic electrode is achieved.

By structured formation of the electrodes, a multiplicity of different detection characteristics can be realized. Interlocking finger electrodes allow, for example, the realization of a slide, with segmented electrodes arranged, for example, multiway switch can be realized. By appropriately fine-structured electrodes, the resolution of the coordinate measuring device can be set defined. Due to the advantageous properties of the electrode material with regard to the use of different production methods, the achievable resolution of the coordinate measuring device thus depends on the fineness of the structures which can be produced in terms of production technology.

In a further embodiment, the electrodes of the first and second electrode arrangement may be structured. By a corresponding design of the evaluation device, detection of at least one force on each surface or electrode arrangement is thus possible.

A / D converters and signal sources are widely used in electronic circuit technology, are often used and are therefore usually very inexpensive available. An evaluation device, which is formed from a signal source and at least one A / D converter, is therefore usually also relatively inexpensive to implement, which is advantageous in view of a widespread use of the coordinate measuring device.

The signal source is designed to emit an electrical alternating signal with a frequency in the range of IkHz to IMHz, preferably a frequency of 25OkHz. The resolution accuracy and resolution of the A / D converter can be adapted in an advantageous manner exactly to the requirements of the capacitance measurement. In particular, it is advantageous that a functionally simple measurement of a capacitance change can be realized by means of a signal source and an A / D converter, for example by determining the changing time constants. It is also advantageous that such electronic components can usually be extremely highly integrated, such integrated circuits can be made compact and space-saving.

In an advantageous development, the signal source and the A / D converter can be formed from organic semiconductors. Components made of organic semiconductors can be produced particularly inexpensively and have decisive advantages with regard to the environmental problems in the production and disposal. When the objective coordinate measuring device is used as intended, it is provided that mechanical contact or force is applied to at least one of the flat sides or the surfaces. A force and possibly also a movement on these surfaces can, however, damage or destroy the electrodes arranged thereon of the first and / or second electrode arrangement. If a protective layer is applied to the first and / or second electrode arrangement, direct contact of the acting force with the electrodes of the electrode arrangement and / or the flat sides of the carrier layer and / or the separation layer not covered by electrodes is advantageously prevented.

In one embodiment, this protective layer can cover the entire coordinate measuring device completely, ie on the electrode arrangements, on the separation layer or on the flat sides of the carrier layer, which are not covered by the electrode arrangement and which are attached to the front side edges. In a further embodiment, however, the protective layer can also be applied only in sections, thus covering, for example, only the portion of the electrodes of the first and / or second electrode arrangement.

Likewise, this protective layer can fully enclose the coordinate measuring device and thus form a hermetic encapsulation of the measuring device. This is particularly advantageous if the measuring device is to be used under particularly difficult environmental conditions.

In a further embodiment, for example, a further layer, in particular a functional layer can be applied. This functional layer can expand the advantageous intrinsic shadows of the protective layer and / or offer an advantageous development with regard to the design possibilities. In particular, this functional layer can be designed to simplify the attachment of design elements such as logo imprints and / or operating elements, so that these elements can be printed, for example, by an inkjet printing process.

Since the electrodes and also the supply and discharge lines of the electrodes are formed from electrically conductive material, it is of decisive advantage if the protective layer is formed of a non-conductive material. With such a training, the protection layer are applied directly to the electrodes of the electrode assemblies or on the supply and discharge lines, since no further precautions need to be taken with regard to the electrical insulation. Another advantage of an electrically non-conductive protective layer is that this protective layer also provides an electrically insulating protection of the coordinate measuring device against the environment, which also has the advantage that no additional insulation measures are required in this case.

In a further embodiment, the protective layer can be formed, for example, from an organic material. The advantageous properties of organic materials with regard to their environmental compatibility thus also apply to a protective layer formed in this way.

With regard to the widest possible field of application of the coordinate measuring device, it is of decisive advantage if the protective layer is resistant to environmental influences. Environmental influences can z. B. (without claim to completeness): moisture, water, temperature, UV light and air (oxygen). Furthermore, the protective layer, for example, also have an increased abrasion resistance and thus also allows use in areas where increased mechanical stress, increased dust pollution and generally with the risk of improper operation is expected.

In a further embodiment, it is conceivable that the protective layer is designed such that it meets the high hygienic standards in the medical field and thus also survives the disinfection process used in this area unscathed.

Also conceivable is an embodiment of the protective layer for protection against acids, alkalis and aggressive vapors.

An electrode arrangement can be structured, for example, to form special contact or switching elements. If at least one further electrode arrangement is applied to the first and / or second electrode arrangement, a completely different structure of the operating elements can be formed with this further electrode arrangement. This makes it possible, for example, to be able to carry out both very coarse position determinations as well as very finely resolved or specially designed position detections with a coordinate measuring device. To avoid disturbing influences, the further electric electrode arrangement with respect to the underlying electrode assembly electrically isolated.

The object of the invention is also achieved by a method, wherein an evaluation device detects the change in the capacitance of the electrodes of the first electrode arrangement and further detects the change in the capacitance of the electrodes of the first and second electrode arrangement. This has the significant advantage that the same time the change in the capacitance of two electrode arrangements can be determined with an evaluation device, without resulting in invalid values due to mutual interference. Furthermore, the claimed embodiment has the advantage that both capacitance values can be determined simultaneously without switching over the electrodes or the evaluation device and also without a time offset

An approach of an object to the electrodes of the first electrode arrangement leads to a change in the detected capacitance between these electrodes. From the measurement of this capacitance change, the position of the object can thus be determined. In a further embodiment, for example, with correspondingly finely structured electrodes of the first and / or second electrode arrangement not only the position of an object can be determined, but can also detect a correspondingly fine structuring several, especially a plurality of objects in their position.

A force on the coordinate measuring device leads to a small deformation in the region of the point of force application. As a result of the changing distance between the electrodes, this deformation also causes a change in the capacitance of the electrodes of the first and second electrode arrangements, which are arranged in the section of the coordinate measuring device influenced by the force. By measuring the change in capacitance of the electrodes of the first and second electrode arrangement, the intensity or strength of the acting force can thus advantageously be determined.

A significant advantage is obtained when the evaluation device is activated by a force acting on the polymer foam. Electrical energy is needed to determine the capacitance change, therefore, it is of crucial advantage in terms of energy efficiency if the capacitance change detection is performed only when in contact with the coordinate measuring machine. The eligible According trained measuring device is therefore at rest, in which it has only a low power consumption. By a Kiafteinwirkung an electric signal is emitted from the polymer foam, which activates the evaluation. For example, a slight tap in any pressure-sensitive section of the coordinate measuring machine is sufficient as a force for activation.

It is also advantageous if, in addition to determining the intensity of a force, it is also possible to determine the direction of the action of force. By a correspondingly structured formation of the electrodes of the first and second electrode arrangement, an acting force causes a change in the capacitance of a plurality of electrodes arranged in this section, from which a direction vector can be calculated.

The invention will be explained in more detail below with reference to the exemplary embodiments illustrated in the drawings.

Show it:

1 shows a sectional view of the pressure-sensitive coordinate measuring device according to the invention;

FIG. 2 shows a greatly simplified electrical equivalent circuit diagram of the individual capacitances of the pressure-sensitive coordinate measuring device; FIG.

FIG. 3 a) b) a plan view of the first and second surfaces of the pressure-sensitive coordinate measuring device with differently structured electrode arrangements; FIG.

4 shows the schematic representation of the electrical sounding, as well as the electrical fields forming;

Fig. 5 a) shows the influence of the electric field of the first electrode arrangement when an object approaches; b) shows the influence of the electric field of the first and second electrode assembly upon a force on the surface. By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with the same reference numerals or the same component designations, wherein the disclosures contained in the entire description can be applied mutatis mutandis to the same parts with the same reference numerals or component names. Also, the position information selected in the description, such as top, bottom, side, etc. related to the immediately described and illustrated figure and are to be transferred to a new position analogous to the new situation. Furthermore, individual features or combinations of features from the different exemplary embodiments shown and described can also represent independent, inventive or inventive solutions.

1 shows a pressure-sensitive coordinate measuring device 1 according to the invention, comprising a carrier layer 2 and a first 3 and second 4 electrode arrangement. On the first 5 and second 6 flat side of the carrier layer 2, a separation layer 7 is applied. The electrodes 8 of the first electrode arrangement 3 and the electrodes 9 of the second electrode arrangement 4 are arranged on the separation layer 7. Optionally, the arrangement may be coated by a protective layer 10, wherein the protective layer over the entire surface, so be arranged on the electrode assemblies, the front side edges of the carrier layer and the separation layer. However, the protective layer can also be arranged only in sections, for example only on the electrode arrangements, or over other discrete sections. Not shown are the electrically conductive connection lines for connecting the electrodes with, also not shown, evaluation device.

The electrodes 8 of the first electrode arrangement 3 and the electrodes 9 of the second electrode arrangement 4 are formed from an electrically conductive material and arranged on the separation layer 7 and / or on the flat sides 5, 6 of the carrier layer 2 such that there is no electrically conductive connection of the individual electrodes can come. If, for example, a polymer foam is used as carrier layer 2, then the separation layer 7 serves to isolate the electrodes from the conductive carrier layer.

In one development, the electrodes of the first and / or second electrode arrangement may be formed, for example, transparent or semitransparent. Therefore, one appears the separation layer 7 applied print image, such as controls and keypads, through the electrodes of the electrode assemblies through. This has the particular advantage that keys or control panels can be formed quickly and easily in this way, whereby different operating characteristics can be realized by different design or arrangement of the electrodes of the electrode arrangements. For example, training as a button, knob and slider are possible.

However, the pressure-sensitive coordinate measuring device according to the invention is not limited to the embodiment described here. In further embodiments, for example, a plurality of separation layers 7 can be arranged between the electrode arrangements and the carrier layer, wherein each separation layer is designed for a different task. For example, the separation layer can serve as an adhesion promoter for the electrodes to be applied thereto.

Since, according to a development, open-cell polymer foams are also used as a carrier layer, the separation layer can also serve as a smoothing layer, since such polymer foams have an uneven surface and can have depressions in particular. For the application of electrodes, it is now advantageous if they can be applied to a surface that is as flat as possible.

Likewise, the pressure-sensitive coordinate measuring device according to the invention is not limited to just one electrode arrangement per flat side of the carrier layer. In order to obtain different measurement characteristics, at least one further electrode arrangement can be arranged, for example, electrically insulated from the first and / or second electrode arrangement. The electrodes of the further electrode arrangement may be formed over a large area, for example, so that only a low local resolution but a high sensitivity is achieved. The measurement of the capacitance change is usually done by measuring the time constant of the decaying alternating signal. By controlling the electrodes of the further electrode arrangements with an alternating signal of a different frequency, for example, a coarse or fine determination of the acting force can be carried out simultaneously. Likewise, the further electrode arrangement can serve to be able to determine the direction of the acting force. Likewise, embodiments are conceivable in which a plurality of protective layers 10 are arranged. For example, in sections in which a control element is located, a protective layer may be applied, which offers increased protection with regard to mechanical loading by an operating means. The entire coordinate measuring device and thus also the sections already covered by a protective layer can subsequently be covered with a further protective layer for the purpose of surface sealing. For example, a protective layer can also be designed as a display element and thus an optional and individually customizable representation of controls and / or allow. Furthermore, the protective layer can also be embodied as a luminous means and thus, for example, serve as background illumination for applied inscriptions.

In an advantageous development, the carrier layer 2, the electrodes 8, 9 of the electrode arrangements 3, 4 and optionally applied separation or protection layers 10 are designed to be flexible. This has the very special advantage that it can also be arranged on non-planar contact surfaces according to the invention pressure-sensitive coordinate measuring device. In particular, however, a continuous, dynamic deformation of the measuring device does not lead to any damage of the same.

2 shows a greatly simplified electrical equivalent circuit diagram of the pressure-sensitive coordinate measuring device 1 according to the invention. On the flat sides 5, 6 of the carrier layer 2, a separation layer 7 is applied in each case. The first electrode arrangement 3 is formed by two individual electrodes 8, the second electrode arrangement 4 is formed by an electrode 9. A first capacitance 11 represents the capacitance between the electrodes 8 of the first electrode arrangement 3. Further capacitances 12 represent the capacitances which form between the electrodes 8 of the first electrode arrangement 3 and the electrode 9 of the second electrode arrangement 4.

By means of an activation of an electrode arrangement with an alternating electrical signal, not shown in the figure, an electric field will be formed between the electrodes. The field of the first electrode arrangement will form substantially in the air, between the first and second electrode arrangement, the field will form substantially in the carrier layer. By appropriate training of the relative permittivity of the separation or the protective layer, the field training can be specifically controlled and so advantageously avoid or reduce mutual interference of the fields.

3 now shows a coordinate measuring device according to the invention with a plurality of differently designed electrode arrangements, FIG. 3 a showing the plan view of the first electrode arrangements and FIG. 3b the plan view of the second electrode arrangements. The electrode arrangements are designed as switches or pushbuttons 13, as multiway switches 14 and as slides 15. Not shown in the figure, the required for measuring the capacitance change evaluation device. The electrodes 8 of the electrode assemblies are connected via connecting lines 16 with this evaluation device.

An inventively designed switch or button 13 now offers the very decisive advantage that a much faster and more reliable detection of the desired function is possible. In the case of a capacitive switch or pushbutton which lacks the possibility of determining an acting force, a desired contact is usually recognized by a longer residence time of the contact-giving object over the electrode arrangement of the switch or pushbutton. In the case of such an input field, which is to be operated, for example, with a finger, the operator must allow his finger to rest on an input field for a certain time, so that the contact can be recognized by the evaluation device. This period of time is required because otherwise a contact would be triggered when moving the input object on the individual panels. The pressure-sensitive coordinate measuring device according to the invention now offers the very special advantage that the contacting, similar to how an operator is accustomed to a keyboard, takes place by pressure on the input element. As a result, a considerably higher input speed is possible and, moreover, an erroneous contact is avoided by unintentionally lingering over an input element. With appropriate design of the carrier layer and / or a separation layer attached thereto, an operator can, for example, also be given a subjective feeling of pressure.

By appropriate training with multiple electrodes 8, a multi-way switch 14 can be realized. Such an operating element can be used, for example, to control a gripping arm. The positioning in a first coordinate plane is effected by determining the position of an input means relative to the electrodes of the multi-way switch 14. The movement of the gripper arm to be controlled in a further coordinate Direction is then carried out by determining the force exerted on the multiway switch pressure. In an advantageous development, for example, with such a Mehrwegschalt- element a joystick be connected, with a combined position and force can be exerted on the multi-way switching element. A further advantageous embodiment is obtained when a control element, such as a joystick, is positively connected to a multi-way switch according to the invention. Such a joystick has a plurality of contacting means, with whose capacity-influencing effect when approaching the electrodes, the position of the contact in the first coordinate plane is determined. A force on the carrier layer leads to a local deformation of the same and thereby to a change in the capacitance value between the electrodes applied thereon. This change in capacitance occurs both in a positive, ie pushing force, as well as in a negative, acting as a pulling force. If the joystick is now non-positively connected to the multi-way switching element, both pressure and tensile forces can be applied to the switching element and thus advantageously achieve a further degree of freedom of the control options.

By interlocking finger electrodes, a slider 15 can be formed. With such a slide, for example, a gripping arm or a pointing element can be moved in a coordinate direction. Due to the advantageous embodiment of the invention, the pressure exerted on the slider pressure can now be used to determine a further coordinate information. For example, the pressure that the contactor object has on the slider can be used to influence the speed of the object to be controlled. As a result, it is advantageously possible, for example, to achieve a very fine and hence very accurate positioning of the object to be controlled by exerting a very low pressure and to achieve a significantly higher control speed of the object by exerting a larger contact pressure with the slider element.

Fig. 3b shows a plan view of the underside of the coordinate measuring device, on which the electrodes 9 of the second electrode arrangements are used up. The counter electrode of the switch or pushbutton 17 and the counterelectrode of the slider 18 are here designed as a planar electrode 9, the counterelectrodes of the multiway switch 19 are two divided educated. In further embodiments, however, these counterelectrodes can also be structured in order to allow further advantageous measuring characteristics. These electrodes are in turn connected via connecting lines 16 with the evaluation device, not shown.

The pressure-sensitive coordinate measuring device according to the invention thus makes it possible to provide a plurality of operating functions with an appropriately designed operating element. A significant advantage of the coordinate measuring device according to the invention is that at the same time a position determination and the determination of locally acting forces is possible.

In further conceivable embodiments, the coordinate measuring device according to the invention can be designed, for example, to determine a load profile. One advantage of the coordinate measuring device according to the invention is that it can be produced very inexpensively, even over a large area. A large-scale measuring device can, for example, for determining the

Fußabrollverhaltens of a runner are used. Likewise, training is conceivable in which the pressure distribution or the load profile of a support to be determined.

In an advantageous development, the carrier layer may for example be designed such that it emits an electrical signal when a force is applied, for example an electrical voltage that wakes a correspondingly designed evaluation device from a power-saving mode. Such a design has the very special advantage that the energy-consuming measurement of the capacitance changes only takes place if this has been triggered by the operator or by an applied force. After carrying out the measurement or after a predetermined time, the evaluation device is automatically placed in a power saving mode, which brings a decisive advantage in terms of the expected operating time, especially for non-mains powered devices.

In a further development, the carrier layer can be designed such that it can generate a force return effect. Thereby, an operator can advantageously be informed immediately which forces occur at the remote controlled device. If, for example, a device is moved over a surface, the nature of the surface on the operating object, for example the operator's finger, can be actively reported back. FIG. 4 shows, in a greatly simplified pressure-sensitive measuring device, the distribution of the electric field that will occur during the measurement of the capacitance or of the capacitance change. The signal source 20 is designed to generate an electrical alternating voltage, in particular a DC voltage-free alternating signal having a frequency which is typically in the range of IkHz to IMHz. The signal source is electrically conductively connected to an electrode 8 of the first electrode arrangement 3. The two other electrodes 8 of the first electrode arrangement 3 and the electrode 9 of the second electrode arrangement 4 are electrically conductively connected to the evaluation device 21, in particular to a signal converter 27.

As a result of the alternating electrical signal applied to the electrode, a first electric field 22 forms between the electrodes of the first electrode arrangement 3. Also between the driven electrode of the first electrode arrangement 3 and the electrode 9 of the second electrode arrangement 4, a second electric field 23 is formed in the material of the carrier layer 2.

The measurement of the capacitance or the capacitance change takes place by a conventional method, for example by determining the time constants. In this case, it is determined by each signal acquisition module 21 how quickly the alternating signal generated by the signal source drops off at the electrode monitored by the signal acquisition module. Using a standard calculation method, the capacitance can now be calculated from this cooldown and used as a reference value for a change in the cooldown and, associated with this, a change in capacitance. To simplify the illustration, neither a separation layer nor a protective layer is shown in FIG. 4. The following description also applies mutatis mutandis to at least one applied separation layer and / or at least one applied protective layer.

5a shows an approximation or pressureless contact of an object 24 with the first electrode arrangement 3, wherein the approximation of the object 24 leads to a distortion of the electric field 25.

FIG. 5 b shows the resulting field influence when the object 24 applies pressure to a portion of the coordinate measuring apparatus 1. An approach of an object or a contact of the first electrode arrangement 3 causes a change in the capacitance value of the first capacitance. As long as there is no deformation of the carrier layer, the capacitance value of the second capacitance remains largely unchanged. If a force is now exerted on the first and / or second electrode arrangement by an object, a small local deformation 26 of the carrier layer 2 occurs in the area of the force. This local deformation causes the distance between the electrodes of the first electrode arrangement 3 and the electrode of the second electrode assembly 4 changes slightly, whereby the capacitance value of the second capacitance changes accordingly.

With correspondingly segmented electrodes of the first electrode arrangement 3, the position of the object approaching or touching the electrode arrangement can now be determined unambiguously by measuring the change in the capacitance values of the first capacitances. In the same way, a determination of the intensity of the action of force is possible by measuring by changing the capacitance values of the second capacitances.

To simplify the illustration, only very simple electrode arrangements were shown in FIG. In further embodiments, both the electrodes of the first electrode order and the electrodes of the second electrode arrangement may be structured. In particular, an advantageous embodiment is conceivable in which, in addition to the position of the contact input in the plane of the first electrode arrangement and the determination of the applied force, the direction of the applied force is also determined. Since an electric field causes local distortions of the electric field in the material of the carrier layer, a directional vector of the acting force can be determined by correspondingly structured electrodes of the second electrode arrangement.

A further advantageous embodiment is obtained if the connection of the electrodes with the signal source or the electrodes with the signal acquisition modules can be changed during the measurement. By means of a corresponding switching or assignment module, it is possible to realize various measuring ranges or measuring characteristics. For example, a plurality of electrodes can thus be interconnected to form a single electrode in order to increase the measuring sensitivity. All statements on ranges of values in objective description are to be understood as including any and all sub-ranges thereof, eg the indication 1 to 10 should be understood to include all sub-ranges, starting from the lower limit 1 and the upper limit 10 ie all subareas begin with a lower one

Limit of 1 or greater and end at an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1 or 5.5 to 10.

The exemplary embodiments show possible embodiments of the pressure-sensitive coordinate measuring device wherein it should be noted that the invention is not limited to the specifically illustrated embodiments thereof, but rather various combinations of the individual embodiments are possible with each other and this variation possibility due to the teaching of technical action by objective invention in the skill of those skilled in this technical field. So are all conceivable embodiments, which are possible by combinations of individual details of the illustrated and described embodiment variant, includes the scope of protection.

For the sake of order, it should finally be pointed out that, for a better understanding of the structure of the pressure-sensitive coordinate measuring device, these or their components have been shown partially unevenly and / or enlarged and / or reduced in size.

The problem underlying the independent inventive solutions can be taken from the description.

Above all, the individual embodiments shown in FIGS. 1 to 5b can form the subject of independent solutions according to the invention. The relevant objects and solutions according to the invention can be found in the detailed descriptions of these figures. REFERENCE NUMBERS

1 coordinate measuring device

2 carrier layer

3 first electrode arrangement

4 second electrode arrangement

5 first flat side

6 second flat side

7 separation layer

8 electrode of the first electrode arrangement 9 electrode of the second electrode arrangement

10 protective layer

11 first capacity 12 second capacity

13 switches or buttons

14 multiway switch

15 slides 16 connecting lines

17 Counter electrode of the switch or button

18 counter electrode of the slider

19 counter electrodes of the multi-way switch

20 signal source

21 evaluation device

22 Electric field of the first electrode arrangement

23 Electric field of the first and second electrode arrangement

24 object

25 field distortion

26 local deformation

27 signal converter, A / D converter

Claims

Patent claims

1. Pressure-sensitive coordinate measuring device (1) comprising at least one carrier layer (2) and at least one first (3) and second (4) electrode arrangement, wherein the carrier layer (2) is formed from an elastically recoverable deformable material and two flat sides (5, 6) which are arranged substantially parallel to one another and are distanced from one another by the thickness of the layer, and wherein the first electrode arrangement (3) is formed by at least two electrically insulated electrodes (8) and on the first flat side (5) of the carrier layer (2) is arranged and wherein the second electrode arrangement (4) by at least one electrode (9) is formed, and on the second flat side (6) of

Carrier layer (2) is arranged is characterized in that the carrier layer (2) is formed by a polymer foam and that an evaluation device (21) for measuring the electrical characteristics of the electrodes (8) of the first electrode assembly (3) and for measuring the electrical characteristics of the Electrodes (8, 9) of the first (3) and second (4) electrode arrangement is formed.

2. Pressure-sensitive coordinate measuring device according to claim 1, characterized in that the polymer foam is closed-cell or open-celled.

3. Pressure-sensitive coordinate measuring device according to claim 1 or 2, characterized in that the polymer foam is formed from a material from the group comprising polypropylene or polyethylene.

4. Pressure-sensitive coordinate measuring device according to one of claims 1 to 3, characterized in that the minimum capacitance of a capacitor of the electrodes (8) of the first electrode assembly (3) and by the electrodes (8, 9) of the first (3 ) and second (4) electrode assembly is greater than 4fF.

5. Pressure-sensitive coordinate measuring device according to one of claims 1 to 4, character- ized in that on the first (5) and / or second (6) flat side of the carrier layer, a separation layer (7) is applied.

6. Pressure-sensitive coordinate measuring device according to one of claims 1 to 5, characterized characterized in that the electrodes (8, 9) are made of polyethylene dioxythiophene (PEDOT).

7. Pressure-sensitive Koordmatenmessvorrichtung according to any one of claims 1 to 6, character- ized in that the electrodes (8, 9) are formed of a transparent conductive material.

8. Pressure-sensitive Koordmatenmessvorrichtung according to any one of claims 1 to 7, characterized in that the electrodes (8, 9) are formed of a metal.

9. Pressure-sensitive Koordmatenmessvorrichtung according to any one of claims 1 to 8, characterized in that the electrodes (8, 9) are structured.

10. Pressure-sensitive coordinate measuring device according to one of claims 1 to 9, character- ized in that the evaluation device (21) from a signal source (20) and at least one A / D converter (27) is formed.

11. Pressure-sensitive coordinate measuring device according to one of claims 1 to 10, characterized in that on the first (3) and / or second (4) electrode arrangement, a protective layer (10) is applied.

12. Pressure-sensitive Koordmatenmessvorrichtung according to any one of claims 1 to 11, characterized in that the protective layer (10) is formed of an electrically non-conductive material.

13. Pressure-sensitive coordinate measuring device according to one of claims 1 to 12, characterized in that the protective layer (10) is resistant to environmental influences.

14. Pressure-sensitive coordinate measuring device according to one of claims 1 to 13, characterized in that at least one further electrode arrangement is arranged on the first (3) and / or second (4) electrode arrangement.

15. Method for determining the position and intensity of a force on a Pressure-sensitive coordinate measuring machine (1) according to one of claims 1 to 14, wherein a force acting on the polymer foam causes a change in the electrical properties of the foam, characterized in that an evaluation device detects the change in the capacitance of the electrodes (8) of the first electrode assembly (3) and further detects the change in the capacitance of the electrodes (9) of the first and second electrode assembly (4).

16. The method according to claim 15, characterized in that from the change of the capacitance of the electrodes (8) of the first electrode assembly (3), the position of the force-effect in the plane of the first electrode assembly (3) is determined.

17. The method according to claim 15 or 16, characterized in that from the change in the capacitance of the electrodes (8, 9) of the first (3) and second (4) electrode arrangement, the intensity of the force is determined.

18. The method according to any one of claims 15 to 17, characterized in that a force on the polymer foam activates the evaluation device (21).

19. The method according to any one of claims 15 to 18, characterized in that the direction of the applied force is determined.