Compact pressure-sensing device
First Claim
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1. A sensing device comprising:
- a planar substrate characterized by a plane;
a beam formed on the substrate, the beam being capable of deflecting in the plane of the substrate into a cavity of the substrate in response to different pressures applied to the beam, wherein the beam deflects according to a difference between a first pressure on a first side of the beam inside the cavity and second pressure on a second side of the beam outside the cavity in a space outside the sensing device; and
a piezo-resistive sensing element coupled to the beam, wherein the piezo-resistive sensing element detects beam deflection responsive to a gas flow outside the cavity adjacent the second side and generates an electrical signal as a function of beam deflection;
wherein the sensing device has a thickness of less than about 100 μ
m.
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Abstract
The innovations herein include a compact sensing device that is capable of measuring the conditions (e,g, pressure, temperature) inside a cylinder of an internal combustion engine. Aspects also include a cost-effective method of fabricating the sensing device. An exemplary sensing device includes a substrate, a beam, and piezo-resistive sensing elements. The beam, which is formed on the substrate, is capable of deflecting according to different pressures applied to different beam surfaces. The piezo-resistive sensing elements are coupled to the beam and detect beam deflection. The piezo-resistive sensing elements generate an electrical signal corresponding to the beam deflection.
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Citations
17 Claims
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1. A sensing device comprising:
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a planar substrate characterized by a plane; a beam formed on the substrate, the beam being capable of deflecting in the plane of the substrate into a cavity of the substrate in response to different pressures applied to the beam, wherein the beam deflects according to a difference between a first pressure on a first side of the beam inside the cavity and second pressure on a second side of the beam outside the cavity in a space outside the sensing device; and a piezo-resistive sensing element coupled to the beam, wherein the piezo-resistive sensing element detects beam deflection responsive to a gas flow outside the cavity adjacent the second side and generates an electrical signal as a function of beam deflection; wherein the sensing device has a thickness of less than about 100 μ
m. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A sensor comprising:
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a flexible material having an electrical interface; a sensing device mounted on the flexible material, the sensing device, the sensing device having a thickness of less than about 100 μ
m and including;a planar substrate characterized by a plane; a cavity formed in the substrate; a beam formed on the substrate, the beam being capable of deflection in the plane of the substrate into the cavity in response to different pressures applied to the beam, wherein the beam deflects according to a difference between a first pressure on a first side of the beam inside the cavity and a second pressure on a second side of the beam outside the cavity in a space outside the sensing device; one or more piezo-resistive sensing elements coupled to the beam, wherein the piezo-resistive sensing elements detect beam deflection responsive to a gas flow outside the cavity adjacent the second side and generate an electrical signal as a function of the beam deflection; and one or more bond pads coupled to the piezo-resistive sensing elements.
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13. A method of fabricating a sensing device, the method comprising:
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providing a planar substrate characterized by a plane; forming a beam on the substrate, the beam configured to deflect in the plane of the substrate into a cavity of the substrate responsive to pressure on different sides of the beam, wherein the beam deflects according to a difference between a first pressure on a first side of the beam inside the cavity and a second pressure on a second side of the beam outside the cavity in a space outside the sensing device; and forming one or more piezo-resistive sensing elements coupled to the beam, wherein the piezo-resistive sensing elements detect beam deflection responsive to a gas flow outside the cavity adjacent the second side and generate an electrical signal as a function of beam deflection; wherein the sensing device fabricated by the method has a thickness of less than about 100 μ
m. - View Dependent Claims (14, 15, 16, 17)
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Specification