US4340409A — Method of fabricating a pressure sensor

Claim 1

Independent Claim 28 words

A method of fabricating a pressure capsule comprising: 1.1 providing two flexible quartz plates having electrodes thereon, wherein the electrodes form the elements of a pressure sensitive capacitor;

Claim 2

Independent Claim 28 words

A method of fabricating a pressure capsule comprising: 1.1 providing two flexible quartz plates having electrodes thereon, wherein the electrodes form the elements of a pressure sensitive capacitor;

Claim 3

Dependent Claim 196 words

2 applying a dielectric sealing glass material, having a predetermined viscosity, to at least one of said quartz plates in the shape of a peripheral seal; 1.3 positioning said quartz plates with said dielectric therebetween in a substantial parallel orientation, at an initial spacing determined by the height of said dielectric; 1.4 decreasing the local pressure proximate the capsule from atmospheric pressure to a lower first pressure level thereby similarly reducing the pressure within the capsule to the first pressure level; 1.5 monotonically increasing the local temperature to a temperature level to reduce the dielectric to a molten glaseous state to encourage outgassing of an organic matter contained in the electrode or dielectric to a molten state; 1.6 increasing the local pressure, in an oxygen enriched environment, to a second pressure level between the range of 1-8 torr of oxygen, to prevent any oxide material in the dielectric from becoming conductive thereby causing an electrical short circuit between the electrodes; 1.7 varying the separation between the plates by clamping the plates together reducing the thickness of the dielectric by increasing the local pressure to a third pressure level after the dielectric has attained said molten state.

Claim 4

Dependent Claim 196 words

2 applying a dielectric sealing glass material, having a predetermined viscosity, to at least one of said quartz plates in the shape of a peripheral seal; 1.3 positioning said quartz plates with said dielectric therebetween in a substantial parallel orientation, at an initial spacing determined by the height of said dielectric; 1.4 decreasing the local pressure proximate the capsule from atmospheric pressure to a lower first pressure level thereby similarly reducing the pressure within the capsule to the first pressure level; 1.5 monotonically increasing the local temperature to a temperature level to reduce the dielectric to a molten glaseous state to encourage outgassing of an organic matter contained in the electrode or dielectric to a molten state; 1.6 increasing the local pressure, in an oxygen enriched environment, to a second pressure level between the range of 1-8 torr of oxygen, to prevent any oxide material in the dielectric from becoming conductive thereby causing an electrical short circuit between the electrodes; 1.7 varying the separation between the plates by clamping the plates together reducing the thickness of the dielectric by increasing the local pressure to a third pressure level after the dielectric has attained said molten state.

Claim 5

Dependent Claim 15 words

The method as recited in claim 1 wherein said third pressure level is approximately atmospheric.

Claim 6

Dependent Claim 46 words

The method as recited in claim 1 further including the following steps: 3.1 decreasing said local pressure to a fourth pressure level intermediate said first and said third pressure levels; 3.2 cooling the capsule; 3.3 increasing said local pressure to atmospheric after the capsule has cooled.

Claim 7

Dependent Claim 75 words

The method as recited in claim 1 wherein said second temperature level is between 650° C.-800° C. and said third temperature level is between 800° C.-1,000° C. and said first pressure level is between 8.0 torr and absolute vacuum, and said second pressure level is between 1.0 torr and 40 torr; and said third pressure level is between 500 torr and atmospheric pressure and said fourth pressure level is between 500 torr and 1.0 torr.

Claim 8

Dependent Claim 55 words

The method as recited in claim 1 wherein; said second temperature level is 700° C. and said third temperature level is 900° C. and said first pressure level is 0.5 torr and said second pressure level is 1.0 torr and said third pressure level is 700 torr and said fourth pressure level is 40 torr.

Claim 9

Dependent Claim 25 words

The method as recited in claim 5 including the additional step of compressively loading said plates prior to the step of decreasing the local pressure.

Claim 10

Dependent Claim 15 words

The method as defined in claim 1 wherein said predetermined viscosity is approximately 200 centi-stokes.

Claim 11

Independent Claim 141 words

A method of mass producing a plurality pressure capsules comprising: 8.1 providing a pair of flexible quartz plates for each capsule having electrodes thereon, wherein the electrodes for the elements of a pressure sensitive capacitor; 8.2 applying a dielectric sealing glass material having a predetermined viscosity to at least one of said quartz plates of each capsule in the shape of a peripheral seal; 8.3 positioning said quartz plates of each capsule with said dielectric therebetween in a substantial parallel orientation at an initial spacing determined by the height of said dielectric; 8.4 placing the capsule in the first temperature zone having a first temperature level which is substantially ambient; 8.5 increasing the capsule temperature by moving the capsule to a temperature zone having a higher temperature level to permit the dielectric to reduce the dielectric to a molten glaseous state;

Claim 12

Independent Claim 141 words

A method of mass producing a plurality pressure capsules comprising: 8.1 providing a pair of flexible quartz plates for each capsule having electrodes thereon, wherein the electrodes for the elements of a pressure sensitive capacitor; 8.2 applying a dielectric sealing glass material having a predetermined viscosity to at least one of said quartz plates of each capsule in the shape of a peripheral seal; 8.3 positioning said quartz plates of each capsule with said dielectric therebetween in a substantial parallel orientation at an initial spacing determined by the height of said dielectric; 8.4 placing the capsule in the first temperature zone having a first temperature level which is substantially ambient; 8.5 increasing the capsule temperature by moving the capsule to a temperature zone having a higher temperature level to permit the dielectric to reduce the dielectric to a molten glaseous state;

Claim 13

Dependent Claim 103 words

6 decreasing the furnace pressure from atmospheric pressure to a lower first pressure level thereby similarly reducing the pressure within each capsule to the first pressure level; 8.7 permitting entrapped gases within the dielectric to outgas; 8.8 clamping the plates by increasing the furnace pressure to a second level to reduce the thickness of the dielectric after the dielectric has attained said molten state; 8.9 decreasing said furnace pressure to a third pressure level intermediate said first and said second pressure levels; 8.10 cooling the capsule by moving the capsule to said first temperature zone; 8.11 increasing the furnace pressure to atmospheric pressure.

Claim 14

Dependent Claim 103 words

6 decreasing the furnace pressure from atmospheric pressure to a lower first pressure level thereby similarly reducing the pressure within each capsule to the first pressure level; 8.7 permitting entrapped gases within the dielectric to outgas; 8.8 clamping the plates by increasing the furnace pressure to a second level to reduce the thickness of the dielectric after the dielectric has attained said molten state; 8.9 decreasing said furnace pressure to a third pressure level intermediate said first and said second pressure levels; 8.10 cooling the capsule by moving the capsule to said first temperature zone; 8.11 increasing the furnace pressure to atmospheric pressure.

Claim 15

Dependent Claim 33 words

The method as recited in claim 1 or 8 wherein said step of clamping includes increasing said furnace pressure to a third pressure level that is less than or equal to atmospheric pressure.

Claim 16

Dependent Claim 15 words

The method as recited in claim 10 wherein said third pressure level is 700 torr.

Claim 17

Dependent Claim 15 words

The method as defined in claim 8 wherein said predetermined viscosity is approximately 200 centi-stokes.

Claim 18

Independent Claim 161 words

A method of fabricating a pressure capsule comprising: providing two flexible quartz plates having electrodes thereon, wherein the electrodes form the elements of a pressure sensitive capacitor; applying a dielectric sealing glass material having a predetermined viscosity to at least one of said quartz plates in the shape of a perimetal seal; positioning said quartz plates with said dielectric therebetween in a substantial parallel orientation, at an initial spacing determined by the initial height of said dielectric; decreasing the pressure within the volume between said plates and said dielectric to a first pressure level that is sufficiently low to encourage outgassing of air entrapped within said dielectric and the electrode material; heating said plates to reduce said dielectric to a molten state; achieving the final spacing between said plates by clamping said plates together to compress the thickness of said dielectric by momentarily increasing the pressure proximate said plates to substantially atmospheric pressure after said dielectric has achieved a molten state.

Claim 19

Independent Claim 161 words

A method of fabricating a pressure capsule comprising: providing two flexible quartz plates having electrodes thereon, wherein the electrodes form the elements of a pressure sensitive capacitor; applying a dielectric sealing glass material having a predetermined viscosity to at least one of said quartz plates in the shape of a perimetal seal; positioning said quartz plates with said dielectric therebetween in a substantial parallel orientation, at an initial spacing determined by the initial height of said dielectric; decreasing the pressure within the volume between said plates and said dielectric to a first pressure level that is sufficiently low to encourage outgassing of air entrapped within said dielectric and the electrode material; heating said plates to reduce said dielectric to a molten state; achieving the final spacing between said plates by clamping said plates together to compress the thickness of said dielectric by momentarily increasing the pressure proximate said plates to substantially atmospheric pressure after said dielectric has achieved a molten state.

Claim 20

Dependent Claim 44 words

The method as defined in claim 12 further including, after the step of heating; preventing said dielectric from exhibiting electrically conductive characteristics by increasing the pressure between said plates, in an oxygen enriched environment, to a second pressure level of 1-8 torr of oxygen.

Claim 21

Dependent Claim 20 words

The method as defined in claim 13 wherein said second pressure level is slightly greater than said first pressure level.

Claim 22

Dependent Claim 49 words

The method as defined in claim 12 further including: permitting said plates to achieve a final parallel orientation and establishing a reference pressure between said plates by pressurizing the volume between said plates to an intermediate pressure level, wherein said intermediate pressure level is between 8 torr and atmospheric.

Claim 23

Independent Claim 17 words

The method as recited in claims 12 or 15 wherein said intermediate pressure level is 40 torr.

Claim 24

Dependent Claim 15 words

The method as defined in claim 12 wherein said predetermined viscosity is approximately 200 centi-stokes.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1985-07-19	1986-01-18	1986-07-20	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1989-07-19	1990-01-18	1990-07-20	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1993-07-19	1994-01-18	1994-07-20	$7700.00	Window Closed / Lapsed

Method of fabricating a pressure sensor

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