Transduction detection device using piezoresistive element and a thermal dissipator element
View Patent ↗A transduction detection device includes a substrate, at least one movable ground relative to the substrate and a suspended stress gauge provided with a piezoresistive element which includes a first anchoring and a second anchoring, different from the first anchoring, relative to the movable ground, wherein it includes at least one thermal dissipator element thermally conductively connected: to a connection portion of the piezoresistive element located outside of the anchorings, and to a thermal discharge part.
1 . A transduction detection device, comprising:
a substrate;
at least one movable ground relative to the substrate;
a suspended stress gauge provided with a piezoresistive element which comprises a first anchoring relative to an anchoring portion and a second anchoring, different from the first anchoring, relative to the movable ground; and
at least one thermal dissipator element thermally conductively connected at a first end to a first connection portion of the piezoresistive element located outside of the first and second anchorings, and at a second end at a second connection portion, to a thermal discharge part of the device, other than the piezoresistive element,
wherein the thermal dissipator element includes an arm extending in a longitudinal direction and having, in a direction perpendicular to its longitudinal direction and to a detection direction, a dimension by height greater than a dimension by height of the piezoresistive element, and
wherein the first end of the thermal dissipator element is directly connected to the piezoresistive element at the first connection portion and the second end of the thermal dissipator element is connected at the second connection portion at the thermal discharge part, and
wherein the first connection portion and the second connection portion are located along a same longitudinal axis of the thermal dissipator arm.
2 . The transduction detection device according to claim 1 , wherein the piezoresistive element is crossed by an electrical current between the first anchoring and the second anchoring when said device is in operation.
3 . The transduction detection device according to claim 1 , wherein the thermal discharge part is one from among the substrate, the movable ground, the first anchoring.
4 . The transduction detection device according to claim 1 , wherein the anchoring portion is a portion of the substrate, and wherein the piezoresistive element comprises a first rigidity, in the detection direction, wherein the piezoresistive element is urged in traction or in compression, and wherein the thermal dissipator element has, in the detection direction, a second rigidity which is strictly less than the first rigidity.
5 . The transduction detection device according to claim 4 , wherein the second rigidity is at least five times lower than the first rigidity.
6 . The transduction detection device according to claim 1 , wherein the thermal dissipator element has, at the connection portion, an oblique main direction relative to a long dimension of the piezoresistive element.
7 . The transduction detection device according to claim 1 , wherein the thermal dissipator element comprises a suspended part extending from the connection portion.
8 . The transduction detection device according to claim 7 , wherein the arm has a shape ratio between a longitudinal dimension and a dimension of the arm in the detection direction of at least 5.
9 . The transduction detection device according to claim 1 , wherein a ratio between the dimension by height of the thermal dissipator element and the dimension by height of the piezoresistive element is greater than 2.
10 . The transduction detection device according to claim 1 , wherein the dimension by height of the thermal dissipator element is greater than 1 μm.
11 . The transduction detection device according to claim 1 , wherein the dimension by height of the thermal dissipator element is greater than 20 μm.
12 . The transduction detection device according to claim 1 , wherein the connection portion is located in the middle of a long dimension of the piezoresistive element.
13 . The transduction detection device according to claim 1 , wherein the thermal dissipator element has a thermal conductance greater than or equal to that of the piezoresistive element.
14 . The transduction detection device according to claim 1 , wherein the thermal dissipator element has at least one degree of freedom of movement relative to the thermal discharge part.
15 . The transduction detection device according to claim 1 , wherein the thermal dissipator element comprises a spring member.
16 . The transduction detection device according to claim 15 , wherein the spring member has a folded shape.
17 . The transduction detection device according to claim 15 , wherein a distal end of the spring member is anchored to the substrate.
18 . The transduction detection device according to claim 1 , wherein the thermal dissipator element comprises a resonance frequency strictly greater than that of an assembly formed by the gauge and the movable ground.
19 . The transduction detection device according to claim 1 , comprising several thermal dissipator elements.
20 . The transduction detection device according to claim 19 , wherein the thermal dissipator elements are each connected to a connection portion of the piezoresistive element, the connection portions cutting the piezoresistive element into sections of identical length along the long dimension of the piezoresistive element.
21 . The transduction detection device according to claim 19 , wherein the thermal dissipator elements are alternately disposed on either side of the long dimension of the piezoresistive element.