CAPACITIVE SENSOR SYSTEM COMPRISING A SENSOR PORTION CONSISTING OF A SYNTHETIC CONSTRUCTION MATERIAL, METHOD FOR THE PRODUCTION OF SAID SYSTEM AND USE OF SAME

Abstract

The invention relates to a capacitive sensor system comprising sensor electronics and a sensor portion (1) consisting of a synthetic construction material which comprises a sensor electrode (3; 22) and to a method for the production and use of said sensor system.

Claims

1. A capacitive sensor system comprising sensor electronics and a sensor portion including a synthetic construction material and a sensor electrode embedded into the synthetic construction material.

2. The capacitive sensor system according to claim 1 with a detection direction (R), characterized by a shield electrode surrounding the sensor electrode at least on a level which is orthogonal to the detection direction (R).

3. The capacitive sensor system according to claim 2, characterized in that the sensor electrode and/or the shield electrode is/are electrically insulated.

4. The capacitive sensor system according to claim 2, characterized by positioning means, which are coupled with the sensor and/or shield electrode(s) and define their position in the sensor portion.

5. The capacitive sensor system according to claim 1, the synthetic construction material characterized by polymer-modified concrete or polymer concrete.

6. The capacitive sensor system according to claim 1, characterized by a plurality of sensor electrodes with stray fields that overlap.

7. The capacitive sensor system according to claim 3, characterized by the arrangement of a plurality of sensor electrodes and the shield electrode on a same level next to each other to form a control panel on a component surface.

8. The capacitive sensor system according to claim 1 with a reinforced sensor portion and an electrical contacting of the reinforcement of the sensor portion.

9. The capacitive sensor system according to claim 8, characterized by an electrical subdivision of the reinforcement into subsections.

10. The capacitive sensor system according to claim 8, wherein the reinforcement is characterized by a flat reinforcement with reinforcement strands running in various directions and at an angle to each other, wherein parallel reinforcement strands are electrically insulated from the reinforcement strands running at the angle to them.

11. The capacitive sensor system according to claim 10, wherein the reinforcement is characterized by a mesh reinforcement made of carbon fibre meshes.

12. The capacitive sensor system according to claim 8, characterized by spacer knit fabric made of a conductive material as the reinforcement.

13. A method of manufacturing a capacitive sensor with a sensor electrode embedded into a synthetic construction material, with the following steps: a) positioning of the sensor electrode and/or of a shield electrode within a formwork device/cast mold, b) introduction of the synthetic construction material into the formwork device, c) allowing the synthetic construction material to harden and stripping the formwork/demolding of the sensor electrode and/or the shield electrode, d) connecting the sensor and/or shield electrodes to an electronics control system.

14. A use of a capacitive sensor with a sensor portion made of a synthetic construction material according to claim 1 as a manually operable control device, in particular for building technology.

Description

[0031] The principle of the invention will be further explained using a drawing for the sake of example. The figures show:

[0032] FIG. 1 a, b, c: Schematic representations for the construction of a sensor portion,

[0033] FIG. 2: a concrete element with a sensor and shield electrode in an exploded view, and

[0034] FIG. 3 tools for manufacturing the concrete element

[0035] FIG. 1a to 1c show sections of three sensor portions 1 of a capacitive sensor system in three basic forms. Altogether, FIG. 1a to 1c show a sensor section 1 made of a flat concrete block 2, in which a plate formed sensor electrode 3 is fully embedded. It is contacted with an electrode connection 4, which runs out of a concrete block 2 to a rear side 11 lying opposite to its upper side 10. The concrete block 2, which is also plate-shaped, has a thickness that corresponds to about three times the thickness of the sensor electrode 3. On its edge side, the concrete block 2 covers it by about three times its thickness. The concrete block 2 is, therefore, a relatively delicate component which encloses the sensor electrode 3 with thin walls and, in its outer shape, corresponds to the shape of the sensor electrode 3.

[0036] An electronics control system, not shown here, and a power source complement the sensor portion 1 shown into a capacitive sensor system. When applying a relatively weak current to the electrode connection 4, the sensor electrode 3 generates an electrostatic stray field 5, which represents the detection field of the sensor electrode 3. In a middle area of the sensor electrode 3, almost vertical field lines 6 are shown, which fall onto the edges 7 in an extremely inclined manner. The vertical field lines 6 define a detection direction R, which defines a direction of action of the capacitive sensor system. If a, generally speaking, earthed solid or fluid body gets into the stray field 5, it represents a second electrode of a capacitor in addition to the sensor electrode 3, the capacitance of which also changes along with the changing distance of the electrodes to each other. Upon approaching the sensor portion 1 against the detection direction R or upon touching the sensor portion 1, a change in voltage occurs which is captured by the electronic control system and is converted into a signal. A control command for an actuator can be generated from this, which opens or closes a switch.

[0037] FIG. 1a shows a sensor portion 1 with an unshielded sensor electrode 3. In contrast, according to FIG. 1b, in addition to the sensor electrode 3, the sensor portion 1 contains a shield electrode 8, which is attached around its circumference, thereby being attached to the narrow side edges of the plate-shaped sensor electrode 3. The shield electrode 8 has a grounding 9, which leads out of the sensor portion 1 as an insulated conductor. It serves to prevent the inhomogeneity of the field 5 at the edges 7 according to FIG. 1a and to limit the stray field 5 to approximately parallel field lines 6. Thereby, the sensitivity of the sensor portion 1 increases so that also smaller changes can be better detected and, at the same level of sensitivity of the sensor system, less power is required for this.

[0038] The stray field 5 of the sensor portion 1 forms at the upper side 10 in the rear side 11 in the same way. FIG. 1c shows a shield electrode 8 which surrounds the plate-shaped sensor electrode 3 on three sides in a sectional view, whereby the stray field 5 is concentrated on the upper side 10 of the sensor portion 3. It also has a grounding 9. Using the shield electrode 8 according to FIG. 1c, a further increase in efficiency of the sensor system can be achieved.

[0039] All known concrete mixtures can, in principle, be used for the concrete block 2. The sensor portion 1, made of the concrete block 2 and the sensor electrode 3 embedded within it, can be attached to the formwork of a concrete wall or its reinforcement or be integrated into brick masonry in the same way as a conventional installation component for example, such as a concrete flush-mounted socket for a switch or a lighting fixture. If the upper side 10 of the concrete block 2 coincides with the surface of the future building wall, the covering of the sensor electrode 3 against the upper side 10 defines the position of the sensor electrode 3 relative to the component surface. Thereby, the concrete block 2 can practically serve as positioning means, which defines the covering of the sensor electrode 3 and its relative position to a functional surface. It affects the spread and intensity of the stray field 5. However, the geometry of the sensor electrode 3, its size and the supplied electrical power can also define the expansion of the electrostatic stray field 5 generated by the sensor electrode 3, thereby defining the degree of touch sensitivity of the capacitive sensor system.

[0040] FIG. 2 shows an exploded view of the sensor portion 1 made of a plate-shaped concrete element 20 in which four rectangular plate-shaped sensor electrodes 22 and four shield electrodes 24 are embedded. The thickness of the concrete element 20 is only 20 mm, its length approximately 1 m and its width approximately 0.5 m. FIG. 2 offers a view of the upper side 10 of the sensor portion 1. The concrete element 20 encloses the four shield electrodes 24 arranged next to each other, which each surrounding a sensor electrode 22 in a frame-shaped manner. Each sensor electrode 22 consists of a metal sheet upturned at the edge, which has a variety of circular breakthroughs 27. In the installed state of the sensor electrode 22, they are filled with concrete and lead to a good interlocking between the sensor electrode 22 and the concrete element 20. Flap-shaped connections 23 of the sensor electrode 22 protrude at the upturns 26 located at the edge. Due to its length, they protrude from a rear side 11 of the concrete element 20, which is concealed in FIG. 2, so that they are not encapsulated with concrete when the sensor portion 1 is manufactured. In particular, each sensor electrode 22 is electrically insulated with relation to the shield electrode 24 as it is bears a plastic-powder coating.

[0041] The shield electrode 24 is principally constructed in a manner similar to the sensor electrode 22. It is also made of a bent sheet material the edge of upturns 28 of which provide for torsional stiffness of the frame-shaped shield electrode 24. The flap-shaped connections 25 protrude at the upturns 28, which protrude out of the future concrete element 20 like the connections 23 of the sensor electrode 22, thereby making an electrical contacting of the shield electrodes 24 possible. The shield electrode 24 also has a plastic-powder coating as an electrical insulation and is riddled with a plurality of circular breakthroughs 27.

[0042] FIG. 3 illustrates the manufacture of the concrete element 20 overhead in an appropriate formwork device 30. A formwork tub 31 determines the outer dimensions of the concrete element 20 according to length and width. A positioning frame 32 can be inserted into it, which is supported by means of edge brackets 33 on an edge 34 of the formwork tub 31 so that it does not touch a base surface 35 of the formwork tub 31. Thereby, it almost hangs into in the formwork tub 31. The shield electrodes 24 can be attached to their connections 25 at pins 36 protruding from it and protruding into the formwork tub 31. The sensor electrodes 22 are attached to the shield electrodes 25 via their connections 23 (not shown). Thereby the position frame 32 holds the sensor electrodes 22 and the shield electrodes 24 at a precisely defined distance over the base surface 35 of the formwork tub 31. Thereby, it defines an installation depth of the electrodes 22, 24 in the concrete element 20 as well as their distance from its surface 10 (FIGS. 1, 2).

[0043] After mounting the sensor electrodes 22 and the shield electrodes 24 in the positioning frame 32 and inserting it into the formwork tub 31, the concrete is introduced. Due to the numerous breakthroughs 27 in the electrodes 22, 24, a more viable connection between the electrodes 22, 24 results on the one hand, and between the future concrete element 20 on the other. At the same time, the electrodes 22, 24 act as a reinforcement for the concrete element 20. Only the connections 23, 25 of the electrodes 22, 24 protrude over a fresh concrete surface so that they and the positioning frame 32 remain untouched by the concrete. After the concrete reaches a sufficient level of stiffness, the positioning frame 32 can be removed and re-used for a subsequent manufacturing step. After full hardening of the concrete in the formwork tub 31, the concrete element 20 can be stripped from the formwork and is available for proper use as a sensor portion 1.

[0044] Since the preceding sensor portions 1 described in detail have to do with exemplary embodiments, they can usually be modified by a person skilled in the art to a further extent without going beyond the scope of the invention. In particular, the specific embodiments of the electrodes 22, 24 can also be formed in a different geometrical shape than what is described here. The sensor section 1 can also be made of other materials and also be designed with a different geometrical shape if this is required due to lack of space or for design reasons. Still, the use of the indefinite article a or an does not rule out that several relevant features can also be present a multiple of times or available several times.

REFERENCE LIST

[0045] 1 Sensor portion [0046] 2 Concrete block [0047] 3 Sensor electrode [0048] 4 Electrode connection [0049] 5 Stray field [0050] 6 Field lines [0051] 7 Pole [0052] 8 Shield electrode [0053] 9 Grounding [0054] 10 Upper side [0055] 11 Rear side [0056] 20 Concrete element [0057] 22 Sensor electrode [0058] 23 Connection [0059] 24 Electrode [0060] 25 Connection [0061] 26 Upturn [0062] 27 Breaks [0063] 28 Upturn [0064] 30 Formwork device/casting mould [0065] 31 Formwork tub [0066] 32 Positioning frame [0067] 33 Bracket [0068] 34 Edge [0069] 35 Floor surface [0070] 36 pin [0071] R Detection direction