PRESSURE AND TEMPERATURE DETERMINING DEVICE, A PRESSURE AND TEMPERATURE SENSOR COMPRISING SUCH A DEVICE AND A METHOD FOR MANUFACTURING SUCH A DEVICE

1 . A pressure and temperature determining device, intended to determine pressures and temperatures of a fluid flowing, for example, in a motor vehicle, the pressure and temperature determining device comprising at least:

a membrane having a contact face intended to be in contact with the fluid,

a pressure determining element secured to the membrane and comprising at least one piezoresistive track sensitive to the pressure,

a temperature determining element which is sensitive to the temperature, and

a support secured to the membrane and configured to support the temperature determining element;

wherein the support has an implantation face which is opposite to the contact face, the temperature determining element being disposed on the implantation face.

2 . The pressure and temperature determining device according to claim 1 , further comprising a base forming the support, the base having a first base face directed toward the membrane and a second base face opposite to the membrane, the second base face forming the implantation face.

3 . The pressure and temperature determining device according to claim 1 , further comprising a printed circuit substrate forming the support, the printed circuit substrate having a first substrate face directed toward the membrane and a second substrate face opposite to the membrane, the second substrate face forming the implantation face.

4 . The pressure and temperature determining device according to claim 1 , wherein the membrane forms the support, and wherein the membrane further has a dry face which is opposite to the contact face, the dry face forming the implantation face.

5 . The pressure and temperature determining device according to claim 1 , wherein the temperature determining element is located, projected on a face of the membrane opposite to the contact face, substantially at the level of a peripheral outline delimiting the pressure determining element.

6 . The pressure and temperature determining device according to claim 5 , wherein a distance between the peripheral outline and a projection of a geometric center of the temperature determining element on the face of the membrane opposite to the contact face is comprised between −25% and +25% of the maximum dimension of the pressure determining element.

7 . The pressure and temperature determining device according to claim 1 , wherein the temperature determining element consists of an electronic component, for example an electronic dipole.

8 . The pressure and temperature determining device according to claim 7 , wherein the temperature determining element comprises a thermistor.

9 . The pressure and temperature determining device according to claim 8 , wherein the thermistor is selected from the group consisting of a Negative Temperature Coefficient thermistor, a Positive Temperature Coefficient thermistor and a platinum resistance thermometer.

10 . The pressure and temperature determining device according to claim 1 , further comprising a securing product arranged so as to fasten the temperature determining element on the implantation face, the securing product being selected from the group consisting of a soldering paste, a solder metal and a weld metal.

11 . A pressure and temperature sensor, intended to measure pressures and temperatures of a fluid flowing, for example, in a motor vehicle, the pressure and temperature sensor comprising at least:

a pressure and temperature determining device according to claim 1 ,

a connecting member configured to fluidly connect the contact face to a pipe for the fluid, and

an electronic unit configured to process signals and connected to the pressure determining element.

12 . The pressure and temperature sensor, according to claim 11 , further comprising a seal, for example an O-ring seal, which is compressed between the contact face and the connecting member, the connecting member having a passage for the fluid, said passage having a section similar to the shape of the seal after compression of the seal.

13 . The pressure and temperature sensor according to claim 12 , wherein the seal defines a perimeter which surrounds the peripheral outline.

14 . A manufacturing method, for manufacturing a pressure and temperature determining device according to claim 1 , the manufacturing method comprising the steps of:

depositing conductive tracks over the membrane,

depositing said at least one piezoresistive track, so as to secure aid at least one piezoresistive track on the membrane,

providing a support secured to the membrane, the support having an implantation face which is opposite to the contact face, and

disposing the temperature determining element on said implantation face.

15 . The manufacturing method according to claim 14 , wherein the conductive tracks depositing step includes depositing through a first silk-screen, and the piezoresistive track depositing step includes depositing through a second silk-screen.