Sensors for measuring distance or position

Abstract

The present invention provides a sensor (1) for measuring distance or position, in particular a capacitive, inductive or eddy current effect sensor (1), with the aim of providing reliable measurement behavior under various environmental conditions using structurally simple means, the sensor (1) comprising a carrier (3) and a sensor element (2) arranged on or integrated with the carrier (3), the sensor (1) being constructed and developed in such a way that the carrier (3) comprises, is based on or consists of a hydrocarbon ceramic laminate.

Description

[Technical Field]

[0001] The present invention relates to a sensor for measuring distance or position, in particular a capacitive, inductive or eddy current effect sensor, which comprises a carrier and a sensor element arranged on or integrated in the carrier. [Background technology]

[0002] In the field of capacitive sensors, for example, sensor elements have for many years been constructed in the form of a sensor surface on a carrier having the form of a printed circuit board. The carrier and the printed circuit board are generally constructed from a composite material consisting of a synthetic resin matrix and a reinforcing material. A particularly preferred type of printed circuit board (FR2) is made from a combination of phenolic resin and paper materials, while the most common type of printed circuit board (FR4) is made from epoxy resin and glass fiber weave. The advantage of this insulating material is that it allows sensors to be brought to market much cheaper and faster than sensors made of metal and insulating / sealing layers or based on sintered ceramic carriers.

[0003] When using a printed circuit board as a carrier or substrate material for a capacitive sensor, it is extremely important that the measurement area of ​​the sensor (usually consisting of copper supported by the carrier material) behaves / expands almost constantly, or at least in an almost calculable and predictable way, even with temperature fluctuations, since the size of the measurement area is very important in capacitive distance measurements. And inexpensive, flexibly configurable capacitive sensor surfaces are often used in industrial environments where temperatures can reach well over 100°C in some applications within factories.

[0004] For inductive sensors or sensors based on the eddy current effect, it is also extremely important that the geometry of the sensor coil (which typically consists of copper windings carried by a carrier material) behaves / expands almost constantly, or at least in an almost calculable and predictable way, even with temperature fluctuations, since the geometry of the coil is very important in inductive / eddy current distance measurements.

[0005] Due to the layer structure of the printed circuit board, the printed circuit board has an anisotropic thermal expansion coefficient Tk. This is generally much lower in the two directions of the plane (x or y direction) than in the direction perpendicular to the plane (z direction). In the case of FR4, the thermal expansion coefficient is, for example, about 12 ppm / °C to 14 ppm / °C in a plane, while it is about 70 ppm / °C in a direction perpendicular to the plane. Generally, the glass transition temperature Tg of FR4 is between 115°C and 140°C, depending on the manufacturer and other additives. At this temperature, the mechanical and electrical properties of the insulating layer change significantly, and the thermal expansion coefficient Tk of the printed circuit board in the direction perpendicular to the plane (i.e., the measurement direction) can "jump" from the typical 70 ppm / °C to approximately 300 ppm / °C. Here, with a rapid deterioration in measurement quality, large forces may be applied to the vias in the printed circuit board, causing them to break and resulting in failure of the sensor.

[0006] The recommended maximum operating temperatures for these FR4-based printed circuit boards are insufficient for many applications because most printed circuit board manufacturers recommend a maximum operating temperature that is approximately 25°C below the glass transition temperature, Tg. Most FR4 printed circuit boards have a Tg of 135°C, and special FR5 printed circuit boards have a Tg of 150°C (high Tg printed circuit boards), but in this case sustained operation at a temperature of 150°C is not possible. Furthermore, conventional FR4 printed circuit board sensors often exhibit unpredictable behavior when measuring distances at elevated temperatures due to the large differences in the expansion coefficients of their individual components (the measuring element, which is based on a printed circuit board, already consists of at least two different main materials: copper and a carrier material, which, if necessary, is bonded to a sensor housing, which is generally made of stainless steel). This is due to the deflection of the capacitive sensor (printed circuit board) due to mechanical stresses resulting from the differential expansion of the individual components in the plane perpendicular to the measurement direction. For sensors that operate based on coils (inductive or eddy current sensors), the geometry of the coil can change (e.g., the diameter changes), which can result in a change in inductance and distorted measurements.

[0007] As an alternative to printed circuit boards made of FR materials, ceramic carriers are used in applications with high temperature requirements. This may be a single-layer ceramic substrate on which conductor tracks are provided by hybrid thick-film printing techniques. Another option is a multi-layer ceramic substrate made of green foil, which can also be printed and assembled in a sintering process to form a rigid printed circuit board. Depending on the temperature range, they are called LTCC (low-temperature cofired ceramics) or HTCC (high-temperature cofired ceramics). However, what all these ceramic technologies have in common is that the resulting printed circuit boards constitute highly rigid and very brittle substrates that have low, if any, resistance to mechanical stress. The different manufacturing processes (printing, sintering, separation by laser or water jet cutting, etc.) make the manufacturing very complex and expensive as well, so these methods are only used in cases of high temperature requirements.

[0008] In the field of such sensors, in view of the high requirements that can arise from the measurement environment, mainly in the industrial sector, it is a constant challenge to be able to develop variably configurable sensors or sensor elements that can be designed and manufactured in a short time and that provide nearly constant measurement characteristics while maintaining maximum independence from the environment. Summary of the Invention [Problem to be solved by the invention]

[0009] It is therefore an object of the invention to specify a sensor as described in the opening paragraph which achieves reliable measurement properties under various environmental conditions using simple construction means. [Means for solving the problem]

[0010] This object is achieved according to the invention by a sensor having the features of claim 1. The sensor is therefore constructed and developed in such a way that the carrier comprises, is based on or consists of a hydrocarbon ceramic laminate.

[0011] Firstly, it has been found within the scope of the present invention that the carrier materials customarily used in known sensors are a limitation to the use of known sensors under a variety of different environmental conditions. Furthermore, it has been found within the scope of the present invention that the above object can be achieved in a surprisingly simple manner by using a hydrocarbon ceramic laminate for the carrier region. In particular, the carrier comprises, is based on, or consists of a hydrocarbon ceramic laminate. Here, various configurations of the present invention can be implemented, and in one variation, for example, the carrier is made entirely of hydrocarbon ceramic laminate. Carriers based on a hydrocarbon ceramic laminate or carriers based on multiple hydrocarbon ceramic laminates can provide an almost direct replacement for flexibly configurable and inexpensive capacitive, inductive / eddy current effect sensors, especially in the field of capacitive, inductive / eddy current effect sensors that include printed circuit boards. Hydrocarbon ceramic laminates are composite materials that may have a matrix of hydrocarbon resin and a reinforcement of glass fiber weave, and the hydrocarbon resin may be filled with a mineral filler (in powder form). These fillers are generally ceramic fillers, although fillers made of other minerals, such as quartz, are also contemplated. Due to the high filling factor, particularly favourable properties similar to those of the ceramic materials mentioned at the outset are achieved. Thus, hydrocarbon ceramic laminates exhibit very consistent mechanical and electrical properties even under widely varying environmental conditions, eg, up to about 280°C. For example, the thermal expansion coefficient is very uniform and its anisotropy is zero or very small. In addition, the thermal expansion coefficient is in the range of 10 ppm / °C to 12 ppm / °C, which is close to the Tk of copper.

[0012] In this way, the sensor according to the present invention provides a sensor that achieves reliable measurement characteristics under a variety of environmental conditions using simple construction means.

[0013] For a particularly simple and reliable construction, the carrier may be configured as or include a printed circuit board. And the use of this printed circuit board as a carrier has been proven to allow flexible and inexpensive manufacturing of the sensor.

[0014] For the production of a particularly reliable and simple sensor, the sensor element may have the form of a sensor element which is introduced into the carrier, coated on the carrier, etched into the carrier, or introduced into a metal layer on the carrier, coated on a metal layer on the carrier, or etched into a metal layer on the carrier, or the form of a sensor surface which is introduced into the carrier, coated on the carrier, etched into the carrier, or introduced into a metal layer on the carrier, coated on a metal layer on the carrier, or etched into a metal layer on the carrier. If the sensor element comprises one or more coils, these may be introduced, applied or etched in the form of conductor tracks or conductor coils.

[0015] In a capacitance type sensor, the sensor element can be configured with a measurement electrode, a guard electrode, and, if necessary, a two-dimensional electrode that forms a ground region. In the case of an inductive or eddy current sensor, the sensor element may consist of one or more coils forming an inductance.

[0016] The sensor elements can then be arranged in a suitable manner in a conductive layer on or in a carrier, thus forming the desired surface or coil. The methods here can involve (selective) etching or laser ablation of copper surfaces, or application of metal surfaces or metal conductors by coating (sputtering, thick film, thin film) or photolithographic methods. It is also conceivable to combine multiple processes, for example, reworking a coil or surface created by coating with laser machining. In printed circuit board technology, the metal planes or conductor tracks are typically made of copper. However, other metals are also suitable, especially in coating processes. This allows the size of the sensor element to be flexibly configured according to each application.

[0017] In a specific configuration, the sensor may have a layer structure consisting of a hydrocarbon ceramic laminate, a hydrocarbon ceramic laminate, at least one copper or metal surface and / or at least one copper or metal conductor track. More specifically, the surface and / or at least one copper or metal conductor track can be applied to or introduced into the hydrocarbon ceramic laminate. Such layering allows for a variety of configuration options to ensure that the sensor configuration can be tailored to a particular application.

[0018] In order to ensure a reliable and simple implementation of the capacitive sensor, in particular at least one copper or metal surface forms the electrode or sensor surface for the capacitive measurement.

[0019] In order to ensure a reliable and simple implementation of the inductive or eddy current effect sensor, in particular at least one copper or metal coil forms the inductance for the inductive or eddy current effect measurement.

[0020] If desired, the sensor may be disposed within, include, or be coupled to the housing. In this respect too, the configuration can be flexibly adapted to the requirements of the respective application of the sensor, and the mounting with a housing ensures a particularly protected configuration and therefore particularly reliable measurement properties.

[0021] In a particular embodiment, the housing may be made of metal. The stability of metal ensures a particularly high level of protection for the sensor element arranged in this housing. Alternatively or additionally, the housing may have at least one mounting through-hole and / or at least one mounting portion. Such mounting through-holes and / or mounting portions allow the sensor to be securely positioned with the housing at the point of use. Precise positioning allows for reliable measurements using the sensor.

[0022] In a particularly simple and reliable form of construction, the sensor or its connection area may have an overmolded or injection-molded envelope. Such an overmolded or injection molded envelope can replace the housing and / or can be reliably achieved using synthetic resins.

[0023] For a particularly reliable operation and / or transmission of measurement data to the evaluation electronics, the sensor element can be in contact with the evaluation electronics via a coaxial or triaxial cable. By using a triaxial coaxial cable, a particularly high shielding effect can be achieved.

[0024] For example, for a simple implementation of a gap sensor, the carrier may have at least two sensor elements measuring different directions. These two directions may be opposite to each other, which makes it particularly easy to measure the gap width.

[0025] In one example embodiment, for a particularly stable construction of the sensor and therefore particularly reliable measurement properties, the sensor or the carrier may comprise a hydrocarbon ceramic stack of multiple layers.

[0026] Also, for a stable construction of the sensor, one or more layers of glass fiber weave may be embedded in a hydrocarbon ceramic laminate. Each layer of the hydrocarbon ceramic laminate may be assigned one or more layers of glass fiber weave. Specifically, multiple layers of glass fiber weave may be embedded or disposed within one layer of hydrocarbon ceramic laminate.

[0027] In one example embodiment, the hydrocarbon ceramic laminate may include at least one filler material, preferably a ceramic powder, more preferably a highly loaded ceramic powder. This in turn makes it possible to achieve a particularly stable sensor structure.

[0028] For a particularly high shielding effect and therefore reliable measurements, the sensor element may have a guard electrode in one layer of the hydrocarbon ceramic stack, and the sensor or carrier may have a further guard electrode in a further layer of the hydrocarbon ceramic stack. This allows a particularly effective shield to be implemented in two stages.

[0029] One exemplary embodiment of the sensor according to the invention allows for the implementation of a capacitive, inductive or eddy current sensor for measuring distance and / or position, with the sensor element being integrated into or applied to a flat substrate acting as a carrier, which substrate consists of or includes a hydrocarbon ceramic laminate.

[0030] Various options exist for advantageously configuring and deploying the features of the present invention. In this respect, reference is first made to the dependent claims and to the following description of preferred embodiments of the sensor according to the invention. In connection with the description of the preferred embodiment examples based on the drawings, preferred embodiments and developments of the present features are also generally described. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a partial cross-sectional side view of a first embodiment of a sensor according to the present invention. [Figure 2] 4A and 4B are a partial cross-sectional side view and a top view of a second embodiment of a sensor according to the present invention. [Figure 3] 10A and 10B are a partial cross-sectional side view and a top view of a third embodiment of a sensor according to the present invention. [Figure 4] FIG. 4 is a perspective view of a third embodiment of the sensor according to the present invention of FIG. 3; [Figure 5] 10A and 10B are a partial cross-sectional side view, a further partial cross-sectional side view, and a top view of a fourth exemplary embodiment of a sensor according to the present invention; [Figure 6] 10A and 10B are a partial cross-sectional side view and a top view of a fifth embodiment of a sensor according to the present invention. [Figure 7] FIG. 10 is a perspective view of a sixth embodiment of a sensor according to the present invention. [Figure 8] FIG. 1 is a cross-sectional view of a hydrocarbon ceramic laminate. [Figure 9] 1 is a cross-sectional view of a sensor according to the present invention having a single layer or multi-layer structure. DETAILED DESCRIPTION OF THE INVENTION

[0032] In the exemplary embodiments of the sensor 1 according to the invention described below, the same reference numerals refer to the same components.

[0033] FIG. 1 shows a first embodiment example of a sensor 1 according to the invention, which comprises a specific capacitive measuring element / sensor element 2 which together with a printed circuit board 3 acting as a carrier 3 forms a composite material, the composite material comprising a hydrocarbon ceramic laminate and copper surfaces and / or copper wiring. The composite material has excellent thermal stability over the entire temperature range of use. The sensor element 2 is located in a metal housing 4 . The contacts are connected via a coaxial cable 5 or a triaxial cable 5 .

[0034] A configuration including a triple coaxial cable 5 will be described below. This configuration has the advantage of improving the shielding effect compared to a coaxial connection of the sensor 1 . The central conductor 6 of the triaxial cable 5 is in contact with a measurement electrode 7 on the sensor element 2 . The inner shielded cable 8 is electrically connected to a metallic shielding cap 9 arranged on the back side of the sensor element 2 . The shield cap 9 is electrically connected to a guard electrode 10 on the front / measurement side of the sensor element 2 . This configuration makes it possible to achieve active shielding of the measurement electrode 7, which is also called guard technology. The outer shield 11 of the triaxial cable 5 is conductively connected to the housing 4 . For this purpose, a metallic support sleeve 12 is pressed against the cable 5 . The support sleeve 12 has two functions: first, it serves to make electrical contact between the outer shield 11 and the housing 4, and second, it supports the cable 5 against the crimping portion 13 which mechanically connects the cable 5 to the housing 4.

[0035] FIG. 2 shows a second embodiment of a sensor 1 according to the invention in a side view A and a top view B. The sensor 1 has a triaxial plug 14 for connection to evaluation electronics (not shown). The housing 4 has two mounting holes 15a and 15b for mounting or positioning the sensor 1 in an appropriate position. For example, the housing 4 can be secured and / or positioned to a suitable member using screws (not shown) that pass through the mounting holes 15a, 15b.

[0036] FIG. 3 shows a third embodiment in which the sensor according to the invention has the form of a capacitive gap sensor 16 in a side view A and a top view B. As in the first embodiment shown in FIG. 1, this gap sensor 16 also comprises a composite material consisting of a capacitive measuring element / sensor element 2 and a printed circuit board 3 acting as a carrier 3, the composite material having a hydrocarbon ceramic laminate and copper surfaces and / or copper wiring.

[0037] The gap sensor 16 has two sensor elements 2 a and 2 b formed on the printed circuit board 3 . One sensor element 2a measures in one direction (upward in the figure), and the other sensor element 2b measures in the opposite direction (downward in the figure). This makes it possible to measure the width of the gap by measuring the distance to one side of the gap and the distance to the other side of the gap at the same time, and determining the width or lateral width of the gap based on this.

[0038] The gap sensor 16 does not have a housing, and is composed only of the composite material consisting of the sensor elements 2a, 2b and the printed circuit board 3 in the measurement area. This is possible due to the good and stable mechanical properties of hydrocarbon ceramic laminates. In the connection area 17, the two sensor elements 2a, 2b are each in contact with a triaxial cable 5a, 5b in a manner known from FIG. Furthermore, two screw holes 18 a and 18 b or through holes are provided or formed in the printed circuit board 3 in order to mechanically fix or position the gap sensor 16 . The entire connection area 17 including the screw holes 18a, 18b is overmolded with a hot melt, in other words, a soluble resin 19. This serves firstly as a mechanical fixation and secondly as a seal against dust and liquids, and acts as a substitute for a housing. However, other injection molding methods may be used instead of hot melt.

[0039] Gap sensor 16 is an example of how such a gap sensor 16 can be flexibly configured. Together with the connection area 17 and the cables 5a, 5b, the printed circuit board 3 forms a complete ultra-thin capacitive sensor 16 that has significantly superior performance compared to comparable sensors for monitoring the gap between two conductive objects. The thickness of such a sensor may be in the range of 0.5 mm to 1.0 mm, preferably 0.8 mm, in the case of a single layer structure of hydrocarbon ceramic laminate, for example.

[0040] FIG. 4 shows an overall perspective view of a gap sensor 16 equipped with triaxial plugs 14a and 14b.

[0041] Figure 5 shows a fourth embodiment of a sensor 1 according to the present invention, which is constructed using only a printed circuit board 3 having a sensor element and already integrated mounting holes 18a, 18b, 18c, and 18d, and a wire 5 without an additional housing, where Figure 5A is a cross-sectional view through the central axis, Figure 5B is a cross-sectional view including the mounting holes as viewed from the side, and Figure 5C is a top view. The sensor 1 comprises multiple layers of hydrocarbon ceramic laminates. The middle (core) layer has a thickness of about 1.5 mm. Three layers, each about 0.5 mm thick, are stacked on top and bottom, giving a total sensor thickness of about 5 mm. The mounting holes 18a, 18b, 18c, and 18d can be formed in the printed circuit board 3 by suitable drilling, cutting, or other methods.

[0042] Also on the printed circuit board 3, this option of three-dimensional cutting and processing allows the capacitive distance sensor to be constructed in a flat design, which gives the option of mounting, for example, without even needing additional components. As shown in FIG. 6, a particularly flat design can be achieved by using a flat cable 20 instead of a cable 5 with a circular cross section.

[0043] FIG. 7 is an overall perspective view showing a sixth embodiment in which the sensor 1 according to the present invention has the form of an eddy current sensor 21 as a flat sensor. The sensor element 22 is composed of a coil 23 arranged on the carrier 3 . Here, coaxial cables 24a and 24b are used with coaxial plugs 25a and 25b. As in the first embodiment shown in FIG. 1, in this area sensor 21, a composite material is formed from a sensor element 22 in the form of a coil 23 and a printed circuit board 3 functioning as a carrier 3, and this composite material has a hydrocarbon ceramic laminate and copper surfaces and / or copper wiring.

[0044] FIG. 8 shows the structure of the hydrocarbon ceramic laminate 27 in cross section. Multiple layers of glass fiber weave 29 are embedded (laminate) in matrix 28 . The matrix 28 contains a filler 30 made of ceramic powder having a high filling rate.

[0045] FIG. 9 shows partial cross-sectional views of a capacitive sensor element 2, where in FIG. 9A the sensor element 2 is positioned on face 31 of a single layer hydrocarbon ceramic laminate 27, and in FIG. 9B the sensor element 2 is embedded in a multilayer printed circuit board 3 made of hydrocarbon ceramic laminates 27a, 27b, and 27c. The sensor element 2 has a measurement electrode 32 and a guard electrode 33 arranged in a circle. To improve the shielding effect, an additional guard electrode 34 is placed at a further location on the printed circuit board and is electrically connected to the guard electrode 33 through a via 35 .

[0046] Advantageous and important aspects of exemplary embodiments of the sensor according to the present invention are described below.

[0047] Printed circuit boards based on hydrocarbon ceramic laminates offer an almost direct replacement for conventional FR4 printed circuit boards for flexibly configurable and inexpensive capacitive, inductive or eddy current effect sensors based on printed circuit board technology.

[0048] These carrier or printed circuit board materials, which have a thermal expansion coefficient very well matched to copper conductor materials and therefore also to stainless steel for any sensor housing, are currently offered by many printed circuit board manufacturers as nearly 1:1 equivalents to FR4 and are very suitable for use in the carrier or printed circuit board of a sensor according to the present invention under varying environmental conditions. The material's good processability, including nearly all processing methods used in printed circuit board manufacturing, makes it even more attractive for the construction and application of the present invention.

[0049] Here, the glass transition temperature, which is important in the case of FR4, is above 280°C. Up to this temperature, the hydrocarbon ceramic laminate (HCL) exhibits very consistent electrical and mechanical properties, making it ideal for developing capacitive sensors cheaply and in the shortest possible time, with very predictable behavior even under large temperature fluctuations. Value Summary: HCL FR4 FR5(HTg) Tg (glass transition temperature) 280℃ 120℃~150℃ ~170℃ Td (destruction temperature) 390℃ Approx. 300℃ Approx. 350℃ Tk(x / y)(ppm / ℃) 10 / 12 Approx. 20 Approx. 20 Tk(z)(ppm / ℃) 32 45~70 45~70 Dielectric constant 3.5 Approx. 4.6 Approx. 4.8 Thermal dielectric constant (ppm / ℃) 50 - -

[0050] These hydrocarbon ceramic laminates make it very simple and inexpensive to manufacture capacitive, inductive or eddy current effect sensors that cover a much wider temperature range than sensors using conventional FR4 printed circuit boards. For this purpose, in a layered structure, copper planes or copper conductor tracks can be applied or introduced onto or into the laminate using known printed circuit board techniques. Here, the copper surfaces form the electrode surfaces (measurement electrodes, guard electrodes, ground areas) or coils (primary coil and secondary coil, if necessary) required for capacitive measurement, which are in contact with copper wires, if necessary via electrical vias. The very similar thermal expansion coefficients Tk of the hydrocarbon ceramic laminate and the copper surface or metal housing result in very little, if any, mechanical stresses that could disturb the measurement or even destroy the sensor, even at high temperatures.

[0051] It is particularly advantageous that conventional manufacturing processes for FR4 technology can be used with little or no modification. For example, flexible printed circuit boards may be laminated onto or between layers of hydrocarbon ceramic laminates to connect sensors according to the present invention. This means that the flat cable for contacting the sensor element can be implemented very simply and cheaply.

[0052] For further advantageous embodiments of the sensor according to the invention, reference is made to the general part of the description and the appended claims to avoid repetition.

[0053] Finally, it is expressly pointed out that the above example embodiments are only used to illustrate the features recited in the claims, and are not intended to limit the scope of the claims to these example embodiments. [Explanation of symbols]

[0054] 1. Sensor 2, 2a, 2b...Sensor element 3. Carrier, printed circuit board 4. Housing 5, 5a, 5b... Wire / cable 6. Center conductor 7. Measurement electrode 8. Shielded cable 9. Shield cap 10. Guard electrode 11. Outer shield 12 Support sleeve 13 Crimping section 14, 14a, 14b... Triaxial plug 15a, 15b Mounting holes 16. Gap sensor 17. Connection area 18a, 18b, 18c, 18d Screw holes, mounting holes 19. Hot melt 20···Flat cable 21 Eddy current sensor 22 Sensor element 23. Coil 24a, 24b Wire / cable 25a, 25b... Coaxial plug 27 Hydrocarbon ceramic laminate 27a-27d Hydrocarbon ceramic laminates 28. Matrix 29. Glass fiber weave 30...Filling material 31...face 32 Measurement electrode 33 Guard electrode 34 Guard electrode 35, 35a, b... via

Claims

1. A sensor (1) for measuring distances or positions, in particular a capacitive, inductive or eddy current effect sensor (1), comprising a carrier (3) and a sensor element (2) arranged on or integrated with said carrier (3), The sensor (1) is characterized in that the carrier (3) comprises, is based on or consists of a hydrocarbon ceramic laminate (27).

2. 2. The sensor according to claim 1, characterized in that the carrier (3) is configured as or includes a printed circuit board (3).

3. 3. The sensor according to claim 1, wherein the sensor element (2) is in the form of a sensor element (2) that is introduced into the carrier (3), or that is coated on the carrier (3), or that is etched into the carrier (3), or that is introduced into a metal layer on the carrier (3), or that is coated on a metal layer on the carrier (3), or that is etched into a metal layer on the carrier (3), or that is in the form of a sensor surface that is introduced into the carrier (3), or that is coated on the carrier (3), or that is etched into a metal layer on the carrier (3), or that is introduced into the carrier (3), or that is coated on a metal layer on the carrier (3), or that is etched into a metal layer on the carrier (3).

4. the sensor (1) has a layer structure consisting of the hydrocarbon ceramic laminate (27), at least one copper or metal surface and / or at least one copper or metal conductor track, 4. The sensor according to claim 1, wherein the surface and / or the at least one copper or metal conductor track can be applied to or introduced into the hydrocarbon ceramic laminate (27).

5. 5. The sensor according to claim 4, characterized in that the at least one copper or metal surface forms an electrode or sensor surface for capacitive measurements.

6. The sensor according to any one of claims 1 to 5, characterized in that the sensor (1) is arranged in, comprises or is connected to a housing (4).

7. 7. The sensor according to claim 6, characterized in that the housing (4) is made of metal and / or has at least one mounting through-hole (15, 18) and / or at least one mounting portion.

8. The sensor according to any one of claims 1 to 7, characterized in that the sensor (1) or the connection area (17) of the sensor (1) is overmolded or has an injection-molded envelope.

9. Sensor according to any one of claims 1 to 8, characterized in that the sensor element (2) is in contact with the evaluation electronics via a coaxial or triaxial cable (5).

10. Sensor according to any one of claims 1 to 9, characterized in that the carrier (3) comprises at least two sensor elements (2a, 2b) measuring in different directions.

11. 11. The sensor according to claim 10, characterized in that the sensor is a gap sensor having sensor elements (2a, 2b) measuring in opposite directions.

12. Sensor according to any one of claims 1 to 11, characterized in that the sensor (1) or the carrier (3) comprises a hydrocarbon ceramic stack (27) of several layers.

13. Sensor according to any one of claims 1 to 12, characterized in that one or more layers of glass fibre weave (29) are embedded in the hydrocarbon ceramic stack (27).

14. The sensor according to any one of the preceding claims, characterized in that the hydrocarbon ceramic stack (27) comprises at least one filler (30), preferably a ceramic powder, more preferably a highly filled ceramic powder.

15. The sensor element (2) has a guard electrode (33) on one layer of the hydrocarbon ceramic laminate (27), The sensor according to any one of claims 1 to 14, characterized in that the sensor (1) or the carrier (3) comprises a further guard electrode (34) in a further layer of the hydrocarbon ceramic stack (27).

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