Capacitive ceramic pressure measuring cell and pressure sensor with such a pressure measuring cell
First Claim
1. A capacitive, ceramic, pressure measuring cell, comprising:
- a ceramic platform; and
a ceramic measuring membrane, which is pressure tightly connected along a peripheral joint with a front side of said platform, forming a reference pressure chamber between said platform and said measuring membrane, wherein;
said measuring membrane has at least a first electrode, which faces said platform;
said platform has at least a second electrode, which faces said measuring membrane;
the capacitance between said first electrode and said second electrode depends on a difference between a pressure externally acting on said measuring membrane and a pressure existing in said reference pressure chamber;
said joint has a thickness, which defines an equilibrium distance between said measuring membrane and the front side of said platform;
on the front side of said platform, a support layer is arranged, which comprises an inorganic insulator;
said support layer has a thickness of at least 0.2 times said thickness of said joint; and
said second electrode is arranged on said support layer.
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Accused Products
Abstract
A capacitive pressure measuring cell, including a ceramic platform and a ceramic measuring membrane, which are connected pressure tightly along a joint to form a reference pressure chamber between them. The measuring membrane has a first electrode facing the platform, and the platform has at least a second electrode facing the measuring membrane. The capacitance between the first and second electrodes depends on the difference between a pressure externally acting on the measuring membrane and a pressure reigning in the reference pressure chamber, wherein the joint has a thickness d, which defines an equilibrium distance between the measuring membrane and the front side of the platform. On the front side of the platform, a support layer is arranged, which comprises an inorganic insulator, wherein the support layer has a thickness of at least 0.2, and wherein the second electrode is arranged on the support layer.
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Citations
14 Claims
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1. A capacitive, ceramic, pressure measuring cell, comprising:
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a ceramic platform; and a ceramic measuring membrane, which is pressure tightly connected along a peripheral joint with a front side of said platform, forming a reference pressure chamber between said platform and said measuring membrane, wherein; said measuring membrane has at least a first electrode, which faces said platform; said platform has at least a second electrode, which faces said measuring membrane; the capacitance between said first electrode and said second electrode depends on a difference between a pressure externally acting on said measuring membrane and a pressure existing in said reference pressure chamber; said joint has a thickness, which defines an equilibrium distance between said measuring membrane and the front side of said platform; on the front side of said platform, a support layer is arranged, which comprises an inorganic insulator; said support layer has a thickness of at least 0.2 times said thickness of said joint; and said second electrode is arranged on said support layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. The pressure sensor, comprising:
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a ceramic platform; and a ceramic measuring membrane, which is pressure tightly connected along a peripheral joint with a front side of said platform, forming a reference pressure chamber between said platform and said measuring membrane, wherein; said measuring membrane has at least a first electrode, which faces said platform; said platform has at least a second electrode, which faces said measuring membrane; the capacitance between said first electrode and said second electrode depends on a difference between a pressure externally acting on said measuring membrane and a pressure existing in said reference pressure chamber; said joint has a thickness, which defines an equilibrium distance between said measuring membrane and the front side of said platform; on the front side of said platform, a support layer is arranged, which comprises an inorganic insulator; said support layer has a thickness of at least 0.2 times said thickness of said joint; and said second electrode is arranged on said support layer; a housing, which has in its interior a pressure measuring cell chamber, in which the pressure measuring cell is arranged; and a clamping apparatus, wherein; said housing has a housing opening, through which said measuring membrane is contactable with a medium; said housing opening has an annular shoulder extending radially inwards, which serves as a sealing surface; a sealing ring is clamped axially between said sealing surface and said measuring membrane; said pressure measuring cell is clamped axially between the clamping apparatus which acts on a rear side of the platform of said pressure measuring cell facing away from said measuring membrane and said sealing ring. - View Dependent Claims (14)
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Specification