SENSOR FOR DETECTING AT LEAST ONE PROPERTY OF A FLUID MEDIUM

Abstract

A sensor for detecting at least one property of a fluid medium is provided. The sensor includes at least one sensor element as well as at least one circuit substrate including at least one control and evaluation circuit. The circuit substrate (112) has at least one projection. At least one temperature sensor is fixed in place on the projection.

Claims

1-11. (canceled)

12. A sensor for detecting at least one property of a fluid medium, comprising: at least one sensor element; at least one circuit substrate having at least one control and evaluation circuit, wherein the circuit substrate has at least one projection; and at least one temperature sensor fixed in place on the projection.

13. The sensor as recited in claim 12, wherein the sensor has a sensor housing including a flow channel, the sensor element being fixed in place on a sensor substrate that projects into the flow channel, and the circuit substrate is situated outside the flow channel in an electronics space of the sensor housing.

14. The sensor as recited in claim 12, wherein the temperature sensor is an SMD component.

15. The sensor as recited in claim 12, wherein the temperature sensor is an NTC.

16. The sensor as recited in claim 12, wherein the sensor is a hot-film air-mass meter.

17. The sensor as recited in claim 12, wherein the temperature sensor is electrically connected to the control and evaluation circuit, and the control and evaluation circuit is configured o consider at least one temperature signal of the temperature sensor in an evaluation of at least one signal of the sensor element.

18. The sensor as recited in claim 12, wherein the circuit substrate is a circuit board.

19. The sensor as recited in claim 12, wherein the projection is a circuit board web.

20. The sensor as recited in claim 12, wherein the circuit board is rectangular, and the projection projects from the circuit board at one corner of the circuit board.

21. The sensor as recited in claim 12, wherein the circuit substrate includes at least one cooling element.

22. The sensor as recited in claim 12, wherein the control and evaluation circuit includes at least one integrated switching circuit, and at least one milled cut for a thermal decoupling of the temperature sensor from the integrated switching circuit is in the circuit substrate between the temperature sensor and the integrated switching circuit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Additional details and optional features of the present invention result from the description below of preferred exemplary embodiments, which are shown in the figures.

[0021] FIG. 1 shows an exploded view of a possible exemplary embodiment of a sensor according to the present invention for detecting at least one property of a fluid medium.

[0022] FIGS. 2A and 2B show two possible exemplary embodiments of circuit substrates to be used in a sensor according to the present invention, in a perspective illustration.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0023] FIG. 1 shows an exemplary embodiment of a sensor 110 for detecting at least one property of a fluid medium 110 according to the present invention. The following FIGS. 2A and 2B show circuit substrates 112 that include a control and evaluation circuit 114, which may be used in sensor 110 according to FIG. 1, for example. These figures are jointly described below.

[0024] In the exemplary embodiment shown in FIG. 1, sensor 110 includes a sensor housing 116 provided with a flow channel 118. Fluid medium is able to enter flow channel 118 through an inlet opening 120, also referred to an inlet, then stream through flow channel 118 and subsequently leave it again through a discharge opening 122, also referred to as an outlet. Sensor 110 as a whole may particularly be developed as a plug-in probe 124 and, for instance, be plugged into a flow tube through which the fluid medium passes. For example, inlet opening 120 points counter to the flow of the fluid medium. Flow channel 118 is able to be sealed by a flow channel cover 126, for example.

[0025] In addition, an electronics space 128 is developed inside sensor housing 116, which accommodates a circuit substrate 112 which includes a control and evaluation circuit 114 situated thereon. Circuit substrate 112 is developed as a circuit board 130, for example, which is glued to a base such as a base plate 132. Connected to base plate 132 is a sensor substrate 134, for instance made of plastic, which projects from electronics space 128 into flow channel 118 in the form of a winglet, for instance. Fixed in place on sensor substrate 134 is a sensor element 136, which is able to be developed in the form of a hot-film air-mass meter sensor chip, for instance. It may have a measuring surface, for example, across which the fluid medium in flow channel 118 is able to flow, the measuring surface having at least one heating element as well as at least two temperature probes, which are disposed in symmetry with respect to the heating element, for example. Sensor element 136 may be connected to circuit board 130 with the aid of wire bonds, for instance.

[0026] For example, circuit substrate 112 is able to be connected to a plug 140 by a conductor comb 138, via which the electrical contacting of sensor 110 may be carried out. During the operation, electronics space 128 may furthermore be sealed by an electronics space cover 142.

[0027] In FIG. 2A, a first possible development of circuit substrate 112 including control and evaluation circuit 114 is shown in a perspective view. It can be gathered that circuit substrate 112, which, for example, may be developed as an essentially rectangular circuit board 130 in this case, may be fitted with a plurality of electronics components 144. In particular, at least one integrated switching circuit 146 may be provided, preferably at least one application-specific integrated switching circuit (ASIC). These electronics components 144 and integrated switching circuit 146, in particular, may produce waste heat.

[0028] In addition, sensor 110 has at least one temperature sensor 148, which may be developed as an SMD-NTC, for instance. However, this temperature sensor is not integrated into sensor housing 116 at a random location and connected to control and evaluation circuit 114 in a complex and costly manner but instead is directly mounted on circuit substrate 112. In order to nevertheless ensure thermal decoupling between temperature sensor 148 and the rest of control and evaluation circuit 114 to which temperature sensor 148 may be electrically connected, circuit substrate 112 is provided with a projection 150. This projection 150 may project from circuit board 130 at an edge 152, for instance. Temperature sensor 148, for example, may be fixed in place on this projection 150, e.g., using SMD technology, in which case projection 150 may be developed as a narrow circuit board web, for instance. This small circuit board web is preferably connected to circuit board 130 via only a small area and thereby largely thermally decoupled from it.

[0029] FIG. 2B shows another exemplary embodiment of circuit substrate 112, which represents a further development of the exemplary embodiment according to FIG. 2A. This example illustrates that additional features and measures may be taken for the thermal decoupling of temperature sensor 148 from control and evaluation circuit 114. In addition to the development of circuit substrate 112 including projection 150, for instance in the form of a circuit board web and/or in the form of the circuit board tab, one or a plurality of cooling fins (not shown) may be provided, for example. Alternatively or additionally, milled cuts 154 may be introduced into circuit board 130, which can be used for an additional thermal decoupling of temperature sensor 148 from integrated switching circuit 146.