DE102008052973B4 - Electrical connection element for sensors - Google Patents

Abstract

Electrical connection element for sensors, in which on a carrier (3) a sensitive element (3.1) is mounted, which is electrically and mechanically connected to an electrical connection conductor (2), wherein a core (1), which consists of a material which has a coefficient of thermal expansion which differs only slightly from the coefficient of expansion of the carrier (3), is wrapped by the connecting conductor (2) and the connecting conductor (2) on one side with a sensor-side terminal (2.1) and on the opposite side with an outer Connection (2.2) ends.

Description

The The invention relates to an electrical connection element for sensors, in which on a support element a semiconductor sensor is mounted, which is connected to an electrical Connecting element is electrically and mechanically connected.

The Invention is particularly for High temperature sensors and for Gas gates suitable. These are usually chips, where on the surface a substrate plate, which preferably consists of ceramic or the like., Electrode structures and / or gas-sensitive metal oxide layers are arranged. Further can arranged on such chips interconnect structures for electrical Heating the chip are provided. As gas-sensitive layers oxide layers are preferably used. Especially because of the high Operating temperatures, it is necessary to use precious metals such as gold, Platinum and / or platinum metals for the electrode structures, heating conductors and also for the contact pads to use. Often become the gas sensor chips with their surface coating passivation layer Mistake.

High temperature sensors are used for measuring the temperature of gaseous media, for example for Measurement of the exhaust temperature of motor vehicles used. They contain a resistance sensor, generally in a protective tube is arranged. In the projecting into the medium area of the protective tube is a high-temperature component with a high temperature chip, its connecting wires are connected to the connecting lines, which are led to the outside, which is usually by means of a mounted in the protective tube sheathed cable he follows.

So is in US Pat. No. 5,497,139 a temperature sensor and a method for its preparation, in which a thermistor is arranged in a heat-resistant housing and the leads are embedded in a chemical compound of the type (Al _1-xy Cr _x Fe _y ) ₂ O ₃ . The disadvantage here is the complicated structure, which has only a low vibration resistance, since at higher temperatures, the protective sheath expands more than the ceramic inner life.

It is also after DE 100 62 041 C2 a temperature sensor is known in which the measuring element is arranged in a protective tube, the connecting line is designed as a jacket tube, which is connected in the region of the measuring element fixed to the protective tube and the measuring element with its connections with the exiting from the jacket tube lines in a temperature-resistant, electrically non-conductive material is poured in the surrounding area of the protective tube. The type of sealing used here of the measuring element to the contact device is not suitable for ensuring long-term stability.

At an in EP 1 426 748 A1 described, provided for the automotive field temperature measuring arrangement, the sensor element is provided with different coaxially arranged protective covers. The arrangement is not suitable for increased vibration stresses.

In the DE 76 29 727 U is a measuring resistor for resistance thermometer with mechanically unloaded feeder described consisting of serving as a carrier ceramic plate, a thin platinum coating as a resistive layer and lead wires, wherein the lead wires through the holes of a short insulator guided and together with this by means of a glass frit layer on the resistive layer and the ceramic plate are attached.

Furthermore, in the DE 967 507 B a method for producing a holder of resistance thermometers described in which a connection between the resistance thermometer and cladding tube by spraying a metal layer, preferably hard metal layer, on which a continuation of the cladding tube forming resistance thermometer is made, such that first a short end of the resistance thermometer from the connection side is inserted into the cladding tube and the freely projecting measuring winding is surrounded in a conventional manner by the metal spray layer, which simultaneously produces a mechanical connection with the cladding tube.

Of the Invention is based on the object, an electrical connection element for sensors of the type mentioned above to improve so that it is synonymous with high thermal and mechanical stresses a long service life guaranteed.

The The object is achieved by an arrangement which the features specified in claim 1 having.

advantageous Embodiments of the invention are the subject of the dependent claims. The Contains connecting element a core made of a material whose thermal expansion coefficient differs only slightly from the coefficient of expansion of the support element. Of the Core is wrapped by a connecting conductor.

This ensures that the connection element has a high electrical conductivity and at the same time adapted to the expansion coefficient of the support element expansion co efficient. The arrangement ensures a high level of safety against vibration stresses.

Of the Core can be made of ceramic, glass or a metal with low thermal Expansion coefficients exist.

A advantageous embodiment provides that the support element and the core is made of ceramic.

Of the Core can be made of ceramic, glass or a metal with low thermal Expansion coefficients exist.

In order to letting both an optimal match the coefficient of expansion as well as a high thermal capacity, especially under dynamic load, achieve.

In a preferred embodiment is used as a connecting conductor, a wire, the usual in semiconductor technology Materials are used. In particular, platinum wires or connecting wires come out platinized titanium used.

Especially suitable is the arrangement for high temperature sensors also for is gas and soot sensors.

One embodiment The invention will be explained in more detail below with reference to a drawing.

In this demonstrate:

1 a schematic representation of a connection element with a connection conductor,

2 a schematic representation of a connection element with two connecting conductors,

3 a connection element in which a core is attached to a ceramic carrier and

4 a connection element, in which two cores are attached to a ceramic housing.

1 shows a connecting element, in which a ceramic core 1 a connection conductor 2 is wound. The connection conductor 2 ends on one side with the sensor-side connector 2.1 and on the opposite side with the outer terminal 2.2 , In the case shown here, the connection conductor consists of platinum wires.

In 2 a connection element is shown, in which two connection conductors 2 around the ceramic core 1 are wound. It is also possible to have several connection conductors 2 around the ceramic core 1 to wrap. The connection conductors 2 are wound at a distance, so that even in uninsulated versions, a touch of the two connecting conductors 2 is prevented.

An application in which a connecting element to a carrier 3 Made of ceramic is in 3 shown. On the carrier 3 are a sensitive element 3.1 , on the connection pads 3.2 the sensor-side connection 2.1 of the connection conductor 2 is welded. The outer connection 2.2 leads to an evaluation unit, not shown here. For a high temperature sensor serves as a sensitive element 3.1 an electrical resistance, preferably in the form of a platinum coil. In a gas sensor is the sensitive element 3.1 from a gas-sensitive semiconductor layer.

4 shows an application in which a connection element to a sensor housing 4 made of ceramic is attached. Here are two cores made of ceramic 1 on the housing 4 attached. The connecting cables 2 are through openings in the housing 4 guided.

1

core

2

connecting conductors

2.1

the sensor side connection

2.2

outer connection

3

carrier

3.1

sensitive element

3.2

contact pad

4

sensor housing

Claims (9)

Electrical connection element for sensors, in which on a support ( 3 ) a sensitive element ( 3.1 ) which is connected to an electrical connection conductor ( 2 ) is electrically and mechanically connected, wherein a core ( 1 ), which consists of a material which has a thermal expansion coefficient which is different from the expansion coefficient of the carrier ( 3 ) differs only slightly from the connection conductor ( 2 ) and the connecting conductor ( 2 ) on one side with a sensor-side connection ( 2.1 ) and on the opposite side with an outer terminal ( 2.2 ) ends. Electrical connection element according to claim 1, characterized in that the carrier ( 3 ) with the sensitive element ( 3.1 ) in a sensor housing ( 4 ) is arranged. Connection element according to claim 1 or 2, characterized in that on the core ( 1 ) several connection conductors ( 2 ) are wound, wherein the connecting conductors ( 2 ) are electrically isolated from each other. Connection element according to claim 1 or 2, characterized in that on the core ( 1 ) several connection conductors ( 2 ) are wound, wherein the connecting conductors ( 2 ) and are not electrically isolated from each other. Connecting element according to one of the preceding claims, characterized in that the carrier ( 3 ) and the core ( 1 ) consist of ceramic. Connecting element according to one of claims 2 to 5, characterized in that the carrier ( 3 ) and the sensor housing ( 4 ) consist of ceramic. Connecting element according to one of the preceding claims, characterized in that the connecting conductor ( 2 ) is a wire. Connecting element according to one of the preceding claims, characterized in that the sensitive element ( 3.1 ) is an electrical resistance. Connecting element according to one of claims 1 to 7, characterized in that the sensitive element ( 3.1 ) is a gas-sensitive semiconductor layer.