US 6,598,483 B2Granted

Capacitive vacuum sensor

AssigneesAnelva Corporation, Masayoshi Esashi

InventorsHaruzo Miyashita, Masayoshi Esashi

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Abstract

A capacitive vacuum sensor includes a non-conducting substrate, a plurality of fixed electrodes on the non-conducting substrate, and a diaphragm electrode formed by a plurality of elastic structures, each of the elastic structures being arranged to oppose a respective one of the fixed electrodes and having a different physical size (area) that is the same as that of each corresponding fixed electrode. More specifically, the areas of the elastic structures have a specific relationship between them, as defined by a specific ratio, and the areas may differ successively from each other according to the specific ratio. The capacitive vacuum sensor further includes compensation electrodes that are not sensitive to any change in the capacitance that may occur in response to any change in the pressure, but is only sensitive to any change in the capacitance that may occur in response to any change in the temperature. The elastic structures forming the diaphragm electrode have a plurality of projections on the surfaces to detach the elastic structures, which have been pressed against by the corresponding fixed electrodes under the higher pressure, away from the corresponding fixed electrodes when the pressure becomes lower.

Claims21

Dependent claims

A capacitive vacuum sensor for providing electrical information to an electrical circuit in response to pressure exerted by a gas, said capacitive vacuum sensor comprising:

a rigid structure comprising a diaphragm electrode portion having a plurality of elastic portions and a rigid portion for supporting said plurality of elastic portions, each of said plurality of elastic portions having an area that is different than the remaining elastic portions, each of said elastic portions arranged so as to contact the gas, each of said elastic portions being capable of deforming a deformation amount that is proportional to its area in response to a pressure exerted by the gas, each area of said elastic portions differs from the remaining areas of said elastic portions such that each respective deformation amount differs successively;
a non-conducting substrate arranged to oppose said rigid structure such that a space is disposed between said non-conducting substrate and said rigid structure;
a plurality of fixed electrodes disposed on a side of said non-conducting substrate, the number of fixed electrodes in said plurality of fixed electrodes is equal to the number of elastic portions in said plurality of elastic portions, each of said fixed electrodes is disposed so as to oppose a respective one of said elastic portions, each of said fixed electrodes having an area equal to the area of said respective one of said elastic portions, whereby a change in capacitance between each fixed electrode and respective elastic portion in response to a deformation of said respective elastic portion in accordance with the pressure exerted by the gas provides electrical information to an electrical circuit such that the pressure of the gas is determined from the electrical information;
and
a plurality of compensating electrodes disposed on said non-conducting substrate, each of said compensating electrodes being disposed adjacent a respective one of said fixed electrodes so as to oppose said rigid portion, each of said compensating electrodes having an area equal to the area of said respective one of said fixed electrodes.

2 more elements

A capacitive vacuum sensor for providing electrical information to an electrical circuit in response to pressure exerted by a gas, said capacitive vacuum sensor comprising:

a rigid structure comprising a diaphragm electrode portion having a plurality of elastic portions and a rigid portion for supporting said plurality of elastic portions, each of said plurality of elastic portions having an area that is different than the remaining elastic portions, each of said elastic portions arranged so as to contact the gas, each of said elastic portions being capable of deforming a deformation amount that is proportional to its area in response to a pressure exerted by the gas, each area of said elastic portions differs from the remaining areas of said elastic portions such that each respective deformation amount differs successively;
a non-conducting substrate arranged to oppose said rigid structure such that a single closed space is disposed between said non-conducting substrate and said rigid structure;
and
a plurality of fixed electrodes disposed on a side of said non-conducting substrate, the number of fixed electrodes in said plurality of fixed electrodes is equal to the number of elastic portions in said plurality of elastic portions, each of said fixed electrodes is disposed so as to oppose a respective one of said elastic portions, each of said fixed electrodes having an area equal to the area of said respective one of said elastic portions, whereby a change in capacitance between each fixed electrode and respective elastic portion in response to a deformation of said respective elastic portion in accordance with the pressure exerted by the gas provides electrical information to an electrical circuit such that the pressure of the gas is determined from the electrical information;
and further consisting
a nonevaparable getter disposed in the single closed space,
wherein said non-conducting substrate has a slit formed thereon for communicating with the single closed space.

4 more elements

A capacitive vacuum sensor for providing electrical information to an electrical circuit in response to pressure exerted by a gas, said capacitive vacuum sensor comprising:

a rigid structure comprising a diaphragm electrode portion having a plurality of elastic portions and a rigid portion for supporting said plurality of elastic portions, each of said plurality of elastic portions having an area that is different than the remaining elastic portions, each of said elastic portions arranged so as to contact the gas, each of said elastic portions being capable of deforming a deformation amount that is proportional to its area in response to a pressure exerted by the gas, each area of said elastic portions differs from the remaining areas of said elastic portions such that each respective deformation amount differs successively;
a non-conducting substrate arranged to oppose said rigid structure such that a space is disposed between said non-conducting substrate and said rigid structure;
a plurality of fixed electrodes disposed on a side of said non-conducting substrate, the number of fixed electrodes in said plurality of fixed electrodes is equal to the number of elastic portions in said plurality of elastic portions, each of said fixed electrodes is disposed so as to oppose a respective one of said elastic portions, each of said fixed electrodes having an area equal to the area of said respective one of said elastic portions, whereby a change in capacitance between each fixed electrode and respective elastic portion in response to a deformation of said respective elastic portion in accordance with the pressure exerted by the gas provides electrical information to an electrical circuit such that the pressure of the gas is determined from the electrical information;
and
electrically conducting leads passing through said non-conducting substrate,
wherein each said lead is capable of providing an electrical connection between said side of said non-conducting substrate and another side of said non-conducting substrate.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/801,721Filed 9 Mar 2001
Priority: JP 2000-06762510 Mar 2000
Published: US 2002/0011114 A131 Jan 2002
Granted: 29 Jul 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

G01L 9/0072
Transmitting or indicating the displacement of flexible diaphragms: using variations in capacitance
G01L 9/0042
Transmitting or indicating the displacement of flexible diaphragms: constructional details associated with semiconductive diaphragm sensors, e.g.…
G01L
Measuring force, stress, torque, work, mechanical power, mechanical efficiency, or fluid pressure