Sensor usable in ultra pure and highly corrosive environments
First Claim
1. A sensor having a non-porous outer surface, said sensor comprising:
- a backing plate having an inner and outer surface;
a non-porous diaphragm having an inner and outer surface, wherein the diaphragm is comprised of a material adapted to be chemically inert and non-contaminating when exposed to an ultra pure chemical process;
a sensing element disposed over the inner surface of the diaphragm; and
glass layer that is bonded by glassing to the inner surface of the backing plate and the inner surface of said non-porous diaphragm proximate an outside periphery thereof, thereby bonding said backing plate and said non-porous diaphragm and enclosing said sensing element within said backing plate, wherein at least one of pressure and temperature near said non-porous diaphragm is detectable by said sensing element, wherein said glass layer has both a high bond strength and a high melt temperature that is at or above 700°
C.
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Accused Products
Abstract
A sensor operable at temperatures in excess of 400° C. is described. The sensor of the present invention operates without fluid fill, is non-porous, non-contaminating, and has no exterior exposed metallic components. The sensor includes a non-porous, impermeable sensing diaphragm that may be positioned in direct contact with fluids in an ultra-pure environment. The non-porous surface may be comprised of a layer of single crystal sapphire that is glassed to a backing plate. The sensor of the present invention is suitable for use in a chemically inert pressure transducer module for sensing pressures and/or temperatures in process fluids and may be molded directly into the high temperature plastic housing of the pressure transducer module.
100 Citations
150 Claims
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1. A sensor having a non-porous outer surface, said sensor comprising:
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a backing plate having an inner and outer surface;
a non-porous diaphragm having an inner and outer surface, wherein the diaphragm is comprised of a material adapted to be chemically inert and non-contaminating when exposed to an ultra pure chemical process;
a sensing element disposed over the inner surface of the diaphragm; and
glass layer that is bonded by glassing to the inner surface of the backing plate and the inner surface of said non-porous diaphragm proximate an outside periphery thereof, thereby bonding said backing plate and said non-porous diaphragm and enclosing said sensing element within said backing plate, wherein at least one of pressure and temperature near said non-porous diaphragm is detectable by said sensing element, wherein said glass layer has both a high bond strength and a high melt temperature that is at or above 700°
C.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
electrical leads coupled to the sensing element that extend through the backing plate;
bond pads disposed between said glass layer and said non-porous diaphragm; and
windows formed in said glass layer providing access to said bond pads, wherein said electrical leads are brazed to said bond pads.
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28. The sensor as recited in claim 1, further comprising a primary seal member disposed on a periphery of the surface of the diaphragm.
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29. The sensor as recited in claim 28, wherein the primary seal member is L-shaped so as to extend along from the periphery of the diaphragm surface to the side of the sensor.
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30. The sensor as recited in claim 28, further comprising a secondary seal member disposed along the side of the backing plate and spaced from the primary seal member.
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31. The sensor as recited in claim 1, wherein the surface of the non-porous diaphragm is coated with a material selected from the group consisting of epoxy, PTFE, PVDF, Paralyne, PEEK, and urethane, wherein the coating is applied to at least a portion of an outer edge of said non-porous diaphragm and said backing plate.
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32. A sensor having a non-porous outer surface, said sensor comprising:
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a backing plate having an inner and outer surface;
a non-porous diaphragm having an inner and outer surface;
means for sensing at least one of temperature and pressure, said sensing means disposed over the inner surface of the diaphragm; and
a glass layer, selected from a glass material having a melt temperature above 700°
C., that is bonded by glassing to the inner surface of the backing plate and the inner surface of said non-porous diaphragm proximate an outside periphery thereof, thereby bonding said backing plate and said non-porous diaphragm, said glass layer having thickness dimension, wherein when the non-porous diaphragm flexes to a desired maximum flexure, a ported of the inner surface of the diaphragm engages an inner surface of the backing plate, wherein at least one of temperature and pressure near said non-porous diaphragm is detectable by said sensing means.- View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57)
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58. A pressure sensor having a non-porous outer surface, said pressure sensor comprising:
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a backing plate having an inner and outer surface and including apertures extending therethrough, said apertures being adapted for receiving electrical leads therethrough;
a non-porous diaphragm having an inner and outer surface;
a sensing element disposed over the inner surface of the diaphragm, said electrical leads coupled to said sensing element;
a metallization layer between the non-porous diaphragm and the backing plate, wherein said metallization layer blocks EMI(RFI from affecting the sensing element; and
a glass layer disposed between the inner surface of the backing plate and the inner surface of said non-porous diaphragm proximate an outside periphery thereof, thereby joining said backing plate and said non-porous diaphragm, wherein a pressure near said non-porous diaphragm is detectable by said sensing element. - View Dependent Claims (59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82)
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83. A pressure sensor having a non-porous outer surface, said pressure sensor comprising:
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a backing plate having an inner and outer surface;
a non-porous diaphragm having an inner and outer surface;
a sensing element disposed over the inner surface of the diaphragm;
a silicon layer positioned between said non-porous diaphragm and the backing plate, wherein said sensing element is formed thereon;
a metalization layer between the silicon layer and the backing plate, wherein said metallization layer blocks affects of EMI/RFI on the sensing element; and
a glass layer disposed between the inner surface of the backing plate and the inner surface of said non-porous diaphragm, wherein a pressure near said non-porous diaphragm is detectable by said sensing element. - View Dependent Claims (84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106)
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107. A sensor having a non-porous outer surface, said sensor comprising:
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a backing plate having an inner and outer surface;
a non-porous diaphragm having an inner and outer surface, wherein the diaphragm is comprised of a material adapted to be chemically inert and non-contaminating when exposed to an ultra pure chemical process;
a conductive layer formed on at least a portion of the inner surface of the diaphragm; and
a glass layer that is bonded by glassing to the inner surface of the backing plate and the inner surface of said non-porous diaphragm proximate an outside periphery thereof, thereby bonding said backing plate and said non-porous diaphragm and enclosing said conductive layer within said backing plate, wherein said glass layer has both a high bond strength and high melt temperature at or above 700°
C.- View Dependent Claims (108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128)
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129. A method of forming a sensor having a non-porous outer surface, the method comprising:
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providing a non-porous diaphragm having an inner and an outer surface, wherein the diaphragm is selected from the group consisting of sapphire and diamond;
forming a sensing element over the inner surface of the non-porous diaphragm;
positioning a backing plate having an inner and an outer surface over at least a portion of the inner surface of the diaphragm and over the sensing element; and
using a glass material layer to bond the inner surface of the backing plate to the inner surface of the diaphragm proximate to an outside periphery of the diaphragm so as to enclose the sensing element, wherein the glass material layer has both a high bond strength and a high melt temperature that is at or above 700°
C.- View Dependent Claims (130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 143, 144, 145)
forming the polymer with carbon powder to form a conductive polymer; and
depositing a conductive ink layer on the backing plate that is electrically connected to the conductive epoxy.
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137. The method of claim 129, wherein the step of providing the diaphragm includes forming the diaphragm with a sensing region having a reduced thickness.
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138. The method of claim 129, further comprising the step of forming a bond pad between the glass layer and the diaphragm.
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139. The method of claim 138, further comprising the step of forming windows in the glass layer to provide an electrical lead access to the bond pad.
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140. The method of claim 139, further comprising the step of forming a silicon layer between the diaphragm and the backing plate and under the sensing element.
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141. The method of claim 129, wherein the step of positioning the backing plate includes forming the backing plate as a single member.
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143. The method of claim 129, wherein the step of providing the diaphragm includes forming the diaphragm with a thickness as a function of a diameter of the diaphragm.
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144. The method of claim 129, further comprising the step of forming a groove in the outer surface of the diaphragm adjacent a glass bond and between the diaphragm and the backing plate.
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145. The sensor as recited in claim 129, further comprising the step of coating the surface of the diaphragm with a material selected from the group consisting of epoxy, PTFE, PVDF, Paralyne, PEEK, and urethane, wherein the coating is applied to at least a portion of an outer edge of said non-porous diaphragm and said backing plate.
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142. The method of claim 142, further comprising the step of forming a Wheatstone bridge from the conductive layer.
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146. A method of forming a sensor having a non-porous outer surface, the method comprising:
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providing a non-porous diaphragm having an inner and an outer surface, wherein the diaphragm is selected from the group consisting of sapphire and diamond;
forming a conductive layer on at least a portion of the inner surface of the diaphragm;
positioning a backing plate having an inner and an outer surface over the inner surface of the diaphragm and over the conductive layer; and
using a glass material to bond the inner surface of the backing plate to the inner surface of the diaphragm proximate to an outside periphery of the diaphragm, wherein the glass material layer has both a high bond strength and a high melt temperature that is at or above 700°
C.
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147. A temperature sensor having a non-porous outer surface, said temperature sensor comprising
a backing plate having an inner and outer surface; -
a non-porous, chemically inert diaphragm having an inner and outer surface, the chemically inert diaphragm selected from a group of materials consisting of sapphire and diamond;
a sensing element disposed over the inner surface of the diaphragm; and
a glass layer that is bonded by glassing to the inner surface of the backing plate and the inner surface of said non-porous diaphragm proximate an outside periphery thereof, thereby bonding said backing plate and said non-porous diaphragm and enclosing said sensing element within said backing plate, the sensing element detecting a temperature change of said non-porous diaphragm as a function of the thickness and conductivity of the chemically inert materials of the diaphragm, wherein the glass layer has both a high bond strength and a high melt temperature that is at or above 700°
C.
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148. A pressure transducer module having therein a sensor with a non-porous outer surface, said the module comprising:
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a pressure and temperature sensor that includes;
a backing plate having an inner and outer surface;
a non-porous, chemically inert diaphragm having an inner and outer surface, the chemically inert diaphragm comprised of a material selected from a group consisting of sapphire and diamond;
a sensing element disposed over the inner surface of the diaphragm;
a glass layer that is bonded by glassing to the inner surface of the backing plate and the inner surface of said non-porous diaphragm proximate an outside periphery thereof, thereby bonding said backing plate and said non-porous diaphragm and enclosing said sensing element within said backing plate, wherein at least one of pressure and temperature near said non-porous diaphragm is detectable by said sensing element, and wherein the glass layer has both a high bond strength and a high melt temperature that is at or above 700°
C.; and
a chemically inert housing adapted to seal the sensor and expose a portion of the diaphragm surface. - View Dependent Claims (149)
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150. A sensor having a non-porous outer surface, said sensor comprising:
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a backing plate having an inner and outer surface;
a sapphire diaphragm having an inner and outer surface, wherein the outer surface includes a coating, the coating being selected from the group consisting of epoxy, PTFE, PVDF, Paralyne, PEEK, and urethane;
a sensing element disposed over the inner surface of the diaphragm;
a glass layer that is bonded by glassing to the inner surface of the backing plate and the inner surface of said sapphire diaphragm proximate an outside periphery thereof, thereby bonding said backing plate and said diaphragm and enclosing said sensing element within said backing plate, wherein at least one of pressure near said diaphragm is detectable by said sensing element, wherein said glass layer has both a high bond strength and a high melt temperature that is at or above 700°
C.
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Specification