DE102010034717B4 - Sensor element for detecting tactile stimuli - Google Patents

Abstract

A sensor element for detecting tactile stimuli, comprising: - a nonconductive, elastically deformable first layer (101) having a first surface, - a nonconductive elastically deformable second layer (102) having a second surface, wherein the first and second surfaces face each other and immediately one or more elastically deformable, electrically conductive first leads (104) disposed on or on the first surface, and spaced from one another by means of spaced apart and elastically deformable spacers (103) between the first and second surfaces; Elastically deformable, electrically conductive second leads (105) disposed on or at the second surface, the first (104) and second (105) leads crossing at intersections, the first (104) and the second (105) 105) lines at the intersections in a mechanically unloaded condition d of the sensor element are spaced from each other.

Description

The invention relates to an elastically deformable, planar sensor element for detecting tactile stimuli, to a device for detecting tactile stimuli with a sensor element of the same type and to a method for producing the sensor element.

A potential field of application for the sensor element is in the field of robotics and telemanipulation, but also especially in the field of medical technology. In these areas, it is desirable to equip grasping fingers, instruments, etc. with a tactile sensor system that allows the human's cutaneous sense of touch to be simulated, for example to determine the position, the shape, the material consistency or the surface structure of objects touched.

Tactile sensors based on planar matrix arrangements of tactile pixels, so-called "taxel" are known. These are generally based on the detection of electrical effects at the intersections of different tracks or electrodes. In each case, a spatially delimited sensitive cell (taxel) is formed at each crossing point. So goes out of the DE 103 41 160 A1 a flat sensor matrix based on a mechanically stable carrier material forth. Tissue-based tactile sensors are used in the DE 10 2004 025 237 A1 and the DE 10 2006 016 661 B4 described. From the DE 10 2007 020 131 A1 goes out a tactile surface sensor with a non-conductive elastic body.

From the DE 37 34 023 A1 is a measuring mat for detecting pressure distribution known. The measuring mat contains a matrix of capacitive pressure transducers, which are formed from the intersections of row conductors and column conductors. Between the row conductors and column conductors, at the intersection of which a dielectric of individual elastic flat bodies is arranged, the size of which essentially corresponds to the intersections of the row and column conductors. The distances between the bodies are so great that, when the measuring mat is bent, the rows or column conductors as well as insulating and shielding materials glued thereon can bulge into the intermediate spaces or be glued into them. For the row and column conductors and the shield metallized textile fabrics and mats knitted from metal threads are used.

From the US 2002/0194934 A1 For example, a force sensor is known that has an electrical property that depends on a predetermined function from a force applied to the force sensor. The force sensor comprises first flexible electrically conductive fibers and second flexible electrically conductive fibers which have an electrical contact at intersections via a piezoresistive connection. The predetermined function describes an electrical resistance that varies inversely with a force applied to the force sensor.

From the DE 200 14 200 U1 is a sensor arrangement for measuring the local distribution of a measured variable, in particular as a sensor seat mat for seat occupancy detection in a motor vehicle known. The sensor arrangement comprises a plurality of sensor elements distributed in a distributed fashion and arranged in matrix form, whose electrical behavior depends on the local value of the measured variable, as well as a plurality of electrical connections connected to the sensor elements in order to detect the electrical behavior of the individual sensor elements by a measuring device. In this case, at least a portion of the sensor elements each consist of a series circuit of a pre-switching element which is independent of the value of the measured variable and a measuring element dependent on the value of the measured variable.

The object of the invention is to provide an elastically deformable sensor element for detecting tactile stimuli, which improves the resolution in the detection of tactile stimuli over the prior art. It is another object of the invention to provide a method for producing the sensor element.

The invention results from the features of the independent claims. Advantageous developments and refinements are the subject of the dependent claims. Other features, applications and advantages of the invention will become apparent from the following description, as well as the explanation of embodiments of the invention, which are illustrated in the figures.

The device-related aspect of the object is achieved with a sensor element for detecting tactile stimuli, comprising: a non-conductive, elastically deformable first layer having a first surface, a non-conductive elastically deformable second layer having a second surface, wherein the first and the second surface facing each other and directly above and between the first and second surfaces individually formed and elastically deformable spacers spaced from each other and connected to each other, one or more elastically deformable, electrically conductive first lines, which are arranged on or on the first surface, and elastically deformable, electrically conductive second conduits disposed on or at the second surface, the first and second conduits intersecting at intersections, the first and second conduits coupling to the first and second conduits Intersection points are spaced apart in a mechanically unloaded state of the sensor element.

Preferably, the first / second leads are disposed in regions of the first / second surface between the spacers. This applies in particular to the intersections. However, the first / second lines can also run in sections or partially below the spacers.

The sensor element according to the invention is based on a film element, which is the subject of a separate patent application filed simultaneously by the applicant with the file reference DE 10 2010 034 719.1 is. The revelation of DE 10 2010 034 719.1 with respect to the film element described therein is hereby incorporated in full in the present disclosure content. In particular, the embodiments describing the film element and the explanatory figures of FIGS DE 10 2010 034 719.1 directed.

In the present application, the film element of the DE 10 2010 034 719.1 supplemented by first and second elastically deformable, electrically conductive lines, which are arranged on or at the first or second surface, wherein first and second lines intersect at intersections.

The inventive arrangement of elastically deformable electrically conductive lines, the film element is a flat tactile sensor element, the particular elastic deformability and the structure of the film element of the DE 10 2010 034 719.1 to improve the directional resolution in the detection of tactile stimuli.

The directional (anisotropic) elastic deformability of the film element is as in DE 10 2010 034 719.1 by a suitable choice of the elastic materials involved (for the first and second layers, for the spacers, as well as for the elastic leads), by a suitable choice of the shape of the spacers, of their arrangement and of their mass, and by a suitable choice the distance with which the first and the second surface are spaced from each other, adjustable during manufacture. With the direction-dependent elastic deformability of the film element, the direction-dependent sensitivity of the sensor element with regard to the detection of tactile stimuli is also defined herein. Thus, the sensor element can be designed according to the requirements of the resolution of tactile stimuli.

In a simple embodiment of the sensor element, the spacers between the first and the second surface are arranged as lattice points of a two-dimensional orthogonal, in particular a Cartesian, lattice. Favor are the first lines parallel to each other and the second lines arranged parallel to each other, while the first and second lines are orthogonal to each other. Of course, any further arrangements of the spacers, for example, with concentric, rectangular geometry, with appropriate arrangement of the first and second lines depending on the task possible. Furthermore, the elastic spacers themselves can take on almost any shape, for example punctiform, star-shaped, oblong, line-shaped, even closed-in forms, such as circles, ellipses, etc.

The areal tactile resolution of the sensor element is determined by the area density of the intersections, in particular of the intersections arranged between the spacers. Each crossing point represents a kind of tactile sensor cell. If the area density of the crossing points in a surface area is large, then the areal tactile resolution of the sensor element for this area area is high. If the area density of the crossing points in a surface area is small, then the areal tactile resolution of the sensor element for this area area is low.

According to the invention, the first and the second lines are spaced apart at the intersection points in a mechanically unloaded state of the sensor element. The term "mechanically unloaded state" means that act on the sensor element no tactile stimuli (forces).

By a force applied to the sensor element (tactile stimulus) approach the first and second lines at the intersection of each other, which may lead to further contact on their approach, and further approach to an elastic deformation of the first and second lines. This approximation of the first and second lines at the crossing points has capacitive or electrical conductivity of the first and second lines relevant measurable effects by means of which the introduced tactile stimuli can be evaluated in a known manner. When the applied force disappears, the "mechanically unloaded state" is established with a hysteresis which is known, manageable and must be taken into account in the evaluation of the abovementioned measurable effects.

In an alternative embodiment of the sensor element, the first and the second lines touch at the crossing points already in the mechanically unloaded state of the sensor element. By applying an external mechanical Force (tactile stimulus) on the sensor element, the first and second lines are now elastically deformed at the respective intersection points affected, which causes each affected a measurable change in the electrical conductivity of the affected lines.

The first and the second layer and the spacers preferably consist of a polymer material, in particular of a silicone material. Furthermore, the first and the second lines preferably consist of an electrically conductive polymer material, such as cis-polyacetylene (PA), trans-polyacetylene (PA) or poly-para-phenylene (PPP). Alternatively, the first and second lines can each consist of a non-conductive and elastically deformable lead body with embedded therein electrically conductive particles.

The first and / or the second layer preferably has a layer thickness of <30 mm, <15 mm, <10 mm, <5 mm, <2 mm, <1 mm, <0.5 mm, <0.1 mm, or <0.05 mm. Depending on the application, the sensor element comprising first and second layers and spacers arranged therebetween has a thickness of <50 mm, <25 mm, <10 mm, <5 mm, <2 mm, <1 mm, <0.5 mm or < 0.1 mm. Furthermore, the distance of the first to the second surface is preferably <15 mm, <10 mm, <5 mm, <3 mm, <2 mm, <1 mm, <0.5 mm, <0.2 mm, <0.1 mm or <0.05 mm. The first and the second surface can be spaced from each other with a constant area distance, but this distance can also vary depending on the application and task area. In a particularly preferred embodiment, the spacers are arranged as grid points of a two-dimensional Cartesian grid having a lattice constant in the range of: <10 mm, <5 mm, <3 mm, <1 mm, <0.5 mm, <0.1 mm, <0.05 mm or <0.01 mm. The intermediate spaces between the spacers and the first and the second surface are preferably filled by a fluid medium, wherein a fluid medium is understood herein to mean a substance which does not resist any slow shear and thus has a finite viscosity. Fluid media therefore include in particular gases and liquids, but also gels. Furthermore, the interspaces of the film element as a whole may be open or closed towards an environment of the film element, i. in the first case, the fluid medium can escape from or penetrate the film element, in particular the external pressure (for example the air pressure) is equal to the internal pressure in the intermediate spaces, in the second case the fluid medium is enclosed in the intermediate spaces. The choice of fluid medium and embodiment (outwardly closed / open spaces) affect the elastic properties of the film element and can be selected according to requirements.

A particularly preferred development of the sensor element is characterized in that the sensor element is formed from a plurality of superimposed sensor elements, i. a plurality of film elements equipped with electrical lines according to the invention are arranged one above the other.

The invention furthermore relates to a tactile sensor having a sensor element according to the above embodiments and to an evaluation module that can be connected to the first and second lines, wherein the evaluation module is a capacitance measuring module, with which electrical capacitance changes can be determined at individual intersection points of the first and second lines, and / or a resistance measuring module, with which an electrical contact resistance at individual crossing points of the first and second lines can be determined, and / or a resistance measuring module with which electrical line resistances of the individual first and second lines can be determined. The location or the affected area of the tactile stimulus on the sensor element as well as the force input associated with the tactile stimulus can be determined from the ascertained capacitance changes or contact resistance changes or changes in resistance.

The procedural aspect of the object is achieved according to a first alternative by a method for producing a sensor element for detecting tactile stimuli, comprising the following method steps: providing an elastically deformable first layer having a first surface, applying of sparsely formed and spaced first spacers a curable polymer material in a first arrangement on the first surface, applying one or more elastically deformable, electrically conductive first lines on or on the first surface between the first spacers, providing an elastically deformable second layer having a second surface, applying a plurality of elastically deformable, electrically conductive second lines on or on the second surface, so that in a subsequent joining of the second surface on the first spacer, at which of the first Ob opposite ends, the second leads are disposed between the spacers, the first and second leads crossing at intersections, moving the first and second layers apart such that the first and second surfaces are a predetermined distance apart and the spacers are the first and second Connect surface directly, curing the Spacer, wherein the polymeric material of the spacer after curing remains elastically deformable and the spacers in a mechanically unloaded state, the first and the second surface at a distance A space.

In one development of the above method, first of all, one or more elastically deformable, electrically conductive first lines are applied to or on the first surface, and then the first spacers made of a curable polymer material are applied in a first arrangement on the first surface, the spacers also can be partially applied to the already existing first lines. The spacers are preferably singulated, i. not touching, upset. Furthermore, the first and second lines are preferably applied to the respective surfaces such that they are arranged in the finished sensor element between the spacers.

Furthermore, according to a second alternative, the method according to the object is achieved by a method for producing a sensor element for detecting tactile stimuli, comprising the following method steps: providing an elastically deformable first layer with a first surface, applying second spacers made of a curable polymer material in a second Arrangement on the first surface, applying one or more elastically deformable, electrically conductive first lines on or at the first surface, providing an elastically deformable second layer having a second surface, applying third spacers made of a curable polymer material in a third arrangement mirror-symmetrical to the second arrangement on the second surface, applying one or more elastically deformable, electrically conductive second leads on or on the second surface, aligning the first and second n layer, so that the arranged on the first and on the second surface of the second and third spacers congruent to each other, joining the respectively congruent opposing second and third spacers at their respective free ends, moving apart of the first and second layers so that the first and second surfaces are a predetermined distance from each other and the spacers connect the first and second surfaces, and curing the spacers, wherein the polymer material of the spacers after curing is elastically deformable and the spacers in a mechanically unloaded state, the first and the second Spaced surface at a distance A.

In a further development of the above method, in each case initially applying one or more elastically deformable, electrically conductive first / second lines on or on the first / second surface and then applying the second / third spacers made of a curable polymer material in a second / third arrangement on the first / second surface, wherein the second / third spacers may also be partially applied to the already existing first / second conduits. Note: The first spacers and the combination of second and third spacers are referred to as "spacers" in the following.

The spacers are preferably singulated, i. not touching, upset. Furthermore, the first and second lines are preferably applied to the respective surfaces such that they are arranged in the finished sensor element between the spacers. This is especially true for the intersections.

Both of these methods are based on methods for producing a film element, which is the subject of the above-mentioned, separate, simultaneously filed patent application of the applicant with the file number DE 10 2010 034 719.1 are. The revelation of DE 10 2010 034 719.1 with respect to the methods described therein, it is hereby incorporated in full in the present disclosure. In particular, the comments on manufacturing methods of the film element and on the explanatory figures of the DE 10 2010 034 719.1 directed.

In the present application, the methods of the DE 10 2010 034 719.1 are supplemented by steps, with which first and second elastically deformable, electrically conductive first and second lines are applied to the first and second layer before the corresponding joining of the first and second layer, wherein the first and second lines intersect at intersections. Depending on the choice of the thickness of the lines and the distance can be adjusted whether the first and second lines in the mechanically unloaded state at the intersection are spaced from each other or they touch each other at the intersections. The first and the second lines are preferably made of an electrically conductive polymer material, such as cis-polyacetylene (PA), trans-polyacetylene (PA) or poly-para-phenylene (PPP). Alternatively, the first and second lines may each consist of a non-conductive and elastically deformable lead body with embedded therein electrically conductive particles. The first and second lines are preferably already before their Application to the first and second surfaces in a cured state, ie cross-linked, vulcanized or cured before. Alternatively, the first and second conduits, analogous to the spacers, may be applied as a curable elastic material and cured in time prior to application of the spacers or together with the spacers.

The curable polymer material of the spacers is preferably a thermoplastic material or a silicone material, the term "curable" being understood here to mean that the elastic material or the polymer material of the spacers does not completely crosslink at the time of application to the first or second surface, or not completely vulcanized or not fully cured.

The application of the spacers or the curable elastic material of the electrical leads is preferably carried out by means of a pressure, molding, casting, injection molding, doctor blade or calendering process. The first surface or the second surface and the spacers applied thereto connect after their application, if necessary, a chemical or physical pretreatment, for example. Heating the first / second surface required.

To set a predetermined deformation behavior of the sensor element, the same or different elastic materials can be used depending on the requirements for the first, the second layer and the spacers. The directional (anisotropic) deformation behavior of the sensor element can be further adjusted by the choice of the arrangement of the spacers. The arrangement of the spacers preferably has a trapezoidal, annular, elliptical or rectangular, in particular square geometry. Of course, depending on the requirements, any further arrangements can be realized. The spacers themselves may take on any shapes that result essentially from the requirements for the sensor element. Thus, the spacers can be cylindrical, wall-like, cubic or designed as a single-shell hyperboloid etc.

After the spacers are joined to the first and second surfaces, the first and second layers are moved apart so that the first and second surfaces are a predetermined distance apart and the spacers connect the first and second surfaces. In any case, the predetermined distance is to be chosen such that the spacers continue to connect the first and second surfaces, i. do not tear or come off one or both of the first and second surfaces. By moving the first and second layers apart, the spacers are changed in their outer shapes. Typically, in this case, a cylindrical or einschalig hyperboloid outer contour of the spacers. Further, by the moving apart, the size of the spaces formed between the first spacers and the first and second surfaces is adjusted. By adjusting the shape of the spacers and the size of the gaps, in turn, the directional (anisotropic) deformation behavior of the film element can be set or adjusted.

After moving apart, curing of the spacers occurs, wherein the polymer material of the spacers remains elastically deformable after curing and the spacers in a mechanically unloaded state space the first and second surfaces at a distance A. The term "curing" is used herein in the sense of "crosslinking", "vulcanizing", "cooling" or "curing", depending on the polymer material used. After curing, the polymeric material of the spacers is elastically deformable and substantially dimensionally stable.

Further advantages, features and details emerge from the following description, in which an exemplary embodiment is described in detail. Described and / or illustrated features form the subject of the invention, or independently of the claims, either alone or in any meaningful combination, and in particular may additionally be the subject of one or more separate applications. The same, similar and / or functionally identical parts are provided with the same reference numerals.

Show it:

1 a schematic representation of a sensor element according to the invention in an oblique view,

2 a schematic representation of the sensor element of 1 in side view, and

3 a schematic representation of the sensor element of 1 respectively. 2 for an application on a three-dimensionally shaped surface.

1 shows a schematic representation of a sensor element according to the invention in an oblique view. Shown is a sensor element with a first layer 101 and a second layer 102 , Both layers are over spacers 103 interconnected and at a distance A spaced apart from each other. The spacers 103 are isolated, arranged in square lattice form. In spaces / cavities between the spacers 103 and the first one 101 and second 102 Layer run first 104 and second 105 electrically conductive, elastically deformable cables. The first lines 104 are parallel to each other. Likewise the second lines 105 , where the first 104 and second 105 Lines intersecting, in the present case orthogonal to each other, are arranged. Furthermore, the first lines 104 at the first surface of the first layer 101 and the second lines 105 and the second surface of the second layer 102 arranged. The intersections are in areas between the spacers 103 arranged. In the mechanically unloaded state, the first intersect 104 and second 105 Non-contacting cables at the crossing points.

By using polymer-based first 103 and second 104 Lines (conductors), the sensor element is designed to be elastically deformable overall. It points between the spacers 103 and the first surface of the first layer 101 and the second surface of the second layer 102 Interspaces / cavities which are presently filled with air. The sensor element can be designed as a highly flexible, thin and elastically extensible sensor element with a suitable choice of the materials and layer thicknesses used. These properties make it possible for the sensor element according to the invention to be applied to strongly curved surfaces, such as a gripper finger of a robot hand, a medical instrument for minimally invasive procedures, etc., in order to reproduce the cutaneous sense of touch of humans and, for example, the position that Form to determine the material consistency or the surface structure of touched objects.

The sensor element allows the detection of various effects of a combined pressure and strain measurement. The following effects are used:

1. Electrical capacity change

At each intersection of the first 104 and second 105 Lines will be between the respective first line 104 and the respective second line forms an electrical capacitor. If a tactile stimulus is applied to the sensor element, then the sensor element is compressed and the first 104 and second 105 Lines approach each other. The electrical capacitance at the respective crossing point changes as a result. This effect can be recorded and evaluated. Due to the special structure of the sensor element with the gaps and spaced by the spacers first 101 and second 102 Layer, this only very small volumes of material must be deformed, so that the first 104 and second 105 Lines approach each other and so a capacity change occurs. As a result, a very high sensitivity is achieved for a tactile stimulation of the sensor element, so that even the smallest touches can be detected. The change in capacitance at the crossing points can also be used for the identification of the pressure intersected points and thus for detecting the pressure distribution on the sensor element.

2. Electrical contact resistance

If the intensity of the tactile stimulus is further increased, the first touches 104 and second 105 Lines at the respective crossing points. This allows us to measure an electrical resistance. With a further increase in the stimulus intensity (increase in force or pressure), the first ones deform 104 and second 105 Lines at the respective intersection points elastic. As a result, the contact area between the lines at the respective crossing points changes and the electrical contact resistance changes. This resistance change can be detected and evaluated for each crossing point.

3. Electrical line resistance in the lines

If a mechanically soft material is used under the sensor element can also in DE 10 2007 020 131 described effect for determining the mechanical strain can be detected. Here, the strain-dependent change in the electrical resistance in the lines is detected and evaluated.

Be the first 104 and second 105 Cables produced, for example, in a pressing or printing process, so the cross section can be chosen almost arbitrary. This can be used to linearize the transfer function of the effect described under point 2. The first used 104 and second 105 Lines in the X or Y direction are present in the mechanically unloaded state of the sensor element by the spacers 103 spatially separated.

2 shows a schematic representation of the sensor element of 1 in side view, in a mechanically unloaded resting state, ie a state in which the sensor element is present, unless a tactile stimulus is introduced. Clearly visible are the spacers 103 , which due to the moving apart of the first 101 and second 102 Layer have a single-shell hyperboloid outer contour during the manufacturing process. The first and second surfaces are spaced apart by a distance A. Furthermore, it can be clearly seen that the first 104 Lines and the second lines 105 Do not touch at the crossroads.

3 shows a schematic representation of the sensor element of 1 respectively. 2 for an application on a three-dimensionally shaped surface. The elastic deformability of the entire sensor element also makes it possible to equip three-dimensionally shaped surfaces, such as, for example, a gripper, a robot finger, etc., with the planar tactile sensor element.

LIST OF REFERENCE NUMBERS

101

elastically deformable, electrically non-conductive first layer

102

elastically deformable, electrically non-conductive second layer

103

spacer

104

elastically deformable, electrically conductive first lines

105

elastically deformable, electrically conductive second lines

Claims (8)

Sensor element for detecting tactile stimuli, comprising: a non-conductive, elastically deformable first layer ( 101 ) having a first surface, - a nonconductive elastically deformable second layer ( 102 ) with a second surface, wherein the first and the second surface facing each other and immediately above between the first and second surfaces isolated formed and elastically deformable spacers ( 103 ) are spaced apart from each other and connected to each other, - one or more elastically deformable, electrically conductive first lines ( 104 ), which are arranged on or at the first surface, and - elastically deformable, electrically conductive second lines ( 105 ) disposed on or at the second surface, wherein the first ( 104 ) and the second ( 105 ) Intersect lines at intersections, with the first ( 104 ) and the second ( 105 ) Lines are spaced at the intersection points in a mechanically unloaded state of the sensor element. Sensor element according to claim 1, characterized in that between the spacers ( 103 ) and the first and the second surface are formed spaces which are filled by a fluid medium. Sensor element according to one of claims 1 or 2, characterized in that the first ( 101 ), the second ( 102 ) Layer and the spacers ( 103 ) consist of silicone material. Sensor element according to one of claims 1 to 3, characterized in that the spacers ( 103 ) are arranged as grid points of a two-dimensional orthogonal, in particular a Cartesian grid, the first lines ( 104 ) parallel to each other and the second lines ( 105 ) are arranged parallel to each other, and the first ( 104 ) and second ( 105 ) Lines are arranged orthogonal to each other. Sensor element according to one of claims 1 or 2, characterized in that the first ( 104 ) and the second ( 105 ) Lines of an electrically non-conductive polymer material with embedded conductive particles. Sensor element according to one of claims 1 to 5, characterized in that the sensor element has a thickness of <1 mm, wherein the first ( 101 ) and the second ( 102 ) Layer each have a layer thickness of <0.1 mm, and the spacers are arranged as lattice points of a two-dimensional Cartesian lattice having a lattice constant in the range of: <1 mm. Tactile sensor with a sensor element according to one of claims 1 to 6, and with an evaluation module, which with the first ( 104 ) and second ( 105 ) Lines, wherein the evaluation module - a capacitance measuring module, with the electrical capacitance changes at individual crossing points of the first ( 104 ) and second ( 105 ) Lines can be determined, and / or - a resistance measuring module with which an electrical contact resistance at individual crossing points of the first ( 104 ) and second ( 105 ) Lines can be determined, and / or - a resistance measuring module, with the electrical line resistance of each first ( 104 ) and second ( 105 ) Lines can be determined has. Method for producing a sensor element for detecting tactile stimuli according to one of claims 1 to 6, comprising the following steps: - providing an elastically deformable first layer ( 101 ) with a first surface, - application of sparsely formed and spaced apart first spacers ( 103 ) of a curable polymer material in a first arrangement on the first surface, - applying one or more elastically deformable, electrically conductive first lines ( 104 ) on or at the first surface between the first spacers, Providing an elastically deformable second layer ( 102 ) having a second surface, - applying a plurality of elastically deformable, electrically conductive second lines ( 105 ) on or at the second surface, such that when the second surface is subsequently joined to the first spacers ( 103 ), at whose ends remote from the first surface, the second lines ( 105 ) are arranged between the spacers, wherein the first ( 104 ) and second lines ( 105 ) at intersections, - moving apart the first ( 101 ) and second ( 102 ) Layer so that the first and second surfaces are a predetermined distance from each other and the spacers ( 103 ) connect the first and second surfaces directly, - curing the spacers ( 103 ), wherein the polymer material of the spacers ( 103 ) remains elastically deformable after curing and the spacers ( 103 ) in a mechanically unloaded state, the first and the second surface at a distance A space.

Images