Sensorelement

Abstract

The invention discloses a sensor element (10) for detecting at least one physical or chemical measurement variable, comprising a planar ceramic substrate (1) having a first surface (3) and a second surface (4) opposite the first surface (3); one or more sensor structures (2) applied to the first surface (3) of the ceramic substrate (1), wherein the sensor structure (2) comprises at least a first contacting region (6) and an end region (12) independent thereof; at least one via (5) from the end region (12) on the first surface (3) to a second contacting region (7) on the second surface (4); and a first connecting line (8) from the first contacting region (6) and a second connecting line (9) from the second contacting region (7).

Description

[0001] The invention relates to a sensor element.

[0002] Sensor elements are used in a wide variety of applications and, depending on their design, are used to measure temperature, flow, gas concentration or composition, humidity, pH, and / or biological parameters, but can also be used as heating elements. Depending on the specific application, the sensor elements often need to be connected, either directly to other sensor elements or to surfaces, for example, directly to the surface to be measured when using a sensor element as a surface probe.

[0003] For today's sensor elements, which are designed according to the current state of the art, various processes are used, such as soldering or gluing.

[0004] If the sensor element is designed as a temperature sensor, for example, it is contacted on one side by two or more wires or strands. The welds are also mechanically fixed with a paste. Both the wires and the strands lead to a raised area in the weld area. If the sensors are to be installed in a pipe, the element must be dimensioned small enough so that the raised area fits within the inner diameter of the pipe. Therefore, the contact areas on the element must also be smaller, which also requires smaller wire diameters.

[0005] Combinations of ceramic elements with metallized plastic strips enable contact on both sides of the plastic strip, as shown, for example, in DE 10 2006 050 694 A1. The assembly of the individual components results in increased complexity. Furthermore, such structures are temperature-limited due to the solder joints and the plastic strip.

[0006] The invention is based on the object of enabling a space-saving design for sensor elements, in particular temperature sensors.

[0007] The object is achieved by a sensor element for detecting at least one physical or chemical measurement variable, comprising a planar ceramic substrate with a first surface and a second surface opposite the first surface; one or more sensor structures which are applied to the first surface of the ceramic substrate, wherein the sensor structure comprises at least a first contacting region and an end region independent thereof; at least one via from the end region on the first surface to a second contacting region on the second surface; and a first connecting line from the first contacting region and a second connecting line from the second contacting region.

[0008] One embodiment provides that the sensor structure or the sensor structures are designed in such a way that the sensor element can be used as a temperature sensor.

[0009] One embodiment provides that the one or more sensor structures consist of a metallic material, in particular platinum, and are applied to the first surface of the ceramic substrate by means of a thin-film or thick-film process.

[0010] One embodiment provides that the sensor element is arranged in a tube.

[0011] One embodiment provides that the tube has a diameter of 1 mm to 12 mm, in particular of 2 mm to 6 mm.

[0012] One embodiment provides that the ceramic substrate is made of aluminum oxide or zirconium oxide.

[0013] One embodiment provides that the first contacting area and the second contacting area are arranged offset from one another.

[0014] One embodiment provides that one or more sensor structures are applied to the second surface of the ceramic substrate.

[0015] This is explained in more detail using the following figures.

[0016] Fig. 1a, b show the claimed sensor element. Fig. 1a shows the sensor element from a first side, Fig. 1b shows the sensor element from a second side.

[0017] The sensor element 10 consists of a planar substrate 1, which is a ceramic material, for example, aluminum oxide or zirconium oxide. Alternatively, the substrate is made of glass. A sensor structure 2 is applied to a first surface 3 of the substrate 1, see Fig. 1a. To protect against environmental influences, e.g. mechanical and / or chemical stress, the sensor structure 2 is at least partially covered with a passivation layer (not shown).

[0018] Sensor structure 2 is a resistance structure or an electrode structure. The sensor element can thus be operated as a temperature sensor or a heating element. However, depending on the number and design of the sensor structures 2, the sensor element can be of various other types, including a temperature sensor, a flow or current sensor, a gas sensor, a humidity sensor, a pH sensor, a biosensor, etc.

[0019] The sensor structures 2 consist of a metallic material, in particular platinum, and are applied to the first surface 3 of the ceramic substrate 1 by means of a thin-film or thick-film process.

[0020] Opposite the first surface 3, the substrate 1 comprises a second surface 4 opposite the first surface 3. The first surface 3 with the sensor structure 2 comprises at least a first contacting region 6 and an independent end region 12. Furthermore, the element 10 comprises at least one via 5 through the substrate 1, specifically from the end region 12 on the first surface 3 to a second contacting region 7 on the second surface 4.

[0021] The through-plating 5 is designed, for example, as a hole through the substrate 1 (for example a drilled or lasered hole), which is filled with a conductive material, for example a metal paste, made of approximately the same material as the sensor structure 2.

[0022] A first connecting line 8, such as a wire or a stranded wire, is connected to the first contacting area 6 (first surface 3); a second connecting line 9 is connected to the second contacting area 7 (second surface 4). The sensor element on the first side 3 thus has at least two "ends" (end area 12 and first contacting area 6). One end is contacted directly on the first side 3. The second end is guided through the substrate 1 by means of the via 5 and contacted on the second side 4.

[0023] The sensor structure 2 is thus conductively connected to at least two electrical contact surfaces 6, 7. The sensor structure 2 can be controlled or electrically operated via the conductive surfaces 6, 7, for example, with an external control and evaluation unit. The contact surfaces 6, 7 are also referred to as the contact area.

[0024] The sensor element 10 can be arranged in a tube 11, for example with a diameter of 1 mm to 12 mm, in particular of 2 mm to 6 mm (see Fig. 1b).

[0025] The resistance element 2 thus has contact areas 6, 7 for wires on both the front side 3 and the back side 4 of the element 10. In one embodiment, the thin film can be structured on both the front and back sides; however, it is also possible to limit the structuring to one side and to create the electrical line and the contact point using a thick film (see above).

[0026] This document describes an element 10 which has at least one contact point 6 on the front side 3 and at least one further contact point 7 on the back side 4, to which wires or strands can be directly welded or soldered.

[0027] A double-sided welded element provides greater temperature resistance. Furthermore, the element can be more easily installed in tubular housings. List of reference symbols 1 ceramic substrate 2 Sensor structure 3 first surface 4 second surface 5 Through-hole plating 6 first contact area 7 second contact area 8 first connecting line 9 second connecting line 10 Sensor element 11 tubes 12 End area QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2006 050 694 A1

[0005]

Claims

[1] Sensor element (10) for detecting at least one physical or chemical measurement variable, comprising - a planar ceramic substrate (1) having a first surface (3) and a second surface (4) opposite the first surface (3); - one or more sensor structures (2) which are applied to the first surface (3) of the ceramic substrate (1), wherein the sensor structure (2) comprises at least a first contacting region (6) and an end region (12) independent thereof; - at least one through-connection (5) from the end region (12) on the first surface (3) to a second contacting region (7) on the second surface (4); and - a first connecting line (8) from the first contacting area (6) and a second connecting line (9) from the second contacting area (7). [2] Sensor element (10) according to claim 1, wherein the sensor structure (2) or the sensor structures (2) are designed such that the sensor element (10) can be used as a temperature sensor. [3] Sensor element (10) according to claim 1 or 2, wherein the one or more sensor structures (2) consist of a metallic material, in particular platinum, and are applied to the first surface (2) of the ceramic substrate (1) by means of a thin-film or thick-film process. [4] Sensor element (10) according to one of the preceding claims, wherein the sensor element (10) is arranged in a tube (11). [5] Sensor element (10) according to the preceding claim, wherein the tube (11) has a diameter of 1 mm to 12 mm, in particular of 2 mm to 6 mm. [6] Sensor element (10) according to one of the preceding claims, wherein the ceramic substrate (11) is made of aluminum oxide or zirconium oxide. [7] Sensor element (10) according to one of the preceding claims, wherein the first contacting region (6) and the second contacting region (7) are arranged offset from one another. [8] Sensor element (10) according to one of the preceding claims, wherein one or more sensor structures (2) are applied to the second surface (4) of the ceramic substrate (1).

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