Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
138 words
A pressure sensor comprising a substrate (116) including substantially oppositely disposed first and second surfaces (134,136); thick film signal conditioning circuitry (126,130) disposed on the first surface (134) and including at least one resistor (120) having a resistance adjustable in response to a signal output by the signal conditioning circuitry; a pressure sensing integrated circuit (110) disposed on the second surface and including a pressure sensitive element (140) and associated circuitry (110) for producing a pressure sensitive output signal; at least one electrically conductive passage (122a,122b) in the substrate coupled to the thick film signal conditioning circuitry and to the associated circuitry; and a ported housing (118) including a ledge (128), the substrate being mounted on the ledge and the or each passage being sealed so as to form a pressurized chamber enclosing the pressure sensing integrated circuit.
Claim 2
Dependent Claim
35 words
A pressure sensor according to claim 1, wherein the or each electrically conductive passage is located adjacent a perimeter of the substrate; the ledge of the ported housing extending along the perimeter of the substrate.
Claim 3
Dependent Claim
40 words
A pressure sensor according to claim 1 or 2, comprising a cover (32) for enclosing the first surface (136) of the substrate after adjustment of the resistance of the or each resistor disposed on the first surface of the substrate.
Claim 4
Dependent Claim
27 words
A pressure sensor according to any one of claims 1 to 3, wherein the substrate is of alumina and the pressure sensing integrated circuit is of silicon.
Claim 5
Independent Claim
130 words
A method of producing a pressure sensor comprising the steps of providing a substrate (116) including first and second surfaces (134,136); providing on the first surface (136) a thick film signal conditioning circuit (126,130) including at least one resistor (120) having an adjustable resistance; providing on the second surface (134) a pressure sensing integrated circuit (110) including a pressure sensitive element (140) and associated circuitry (110) for producing a pressure sensitive output signal; providing on the substrate at least one electrically conductive passage (122a,122b) for electrically interconnecting the thick film signal conditioning circuit and the associated circuitry; and enclosing the second surface (134) of the substrate by means of a ported housing (128) and substantially simultaneously sealing the or each electrically conductive passage so as to form a pressurisable chamber.
Claim 6
Dependent Claim
21 words
A method according to claim 5, wherein the or each electrically conductive passage is located adjacent a perimeter of the substrate.
Claim 7
Dependent Claim
55 words
A method according to claim 5 or 6, comprising the steps of pressurizing the chamber so as to cause the pressure sensitive integrated circuit and the signal conditioning circuit to produce an output signal; and adjusting the resistance of the or each resistor (120) disposed on the first surface in response to the output signal.
Claim 8
Dependent Claim
24 words
A method according to claim 7, comprising the step of enclosing the first surface of the substrate after adjustment of the or each resistor.
Claim 9
Dependent Claim
21 words
A method according to claim 8, wherein the substrate is enclosed in a manner as to make the pressure sensor air-tight.
Claim 10
Dependent Claim
35 words
A method according to claim 8 or 9, comprising the step of passivating the first surface of the substrate after adjustment of the or each resistor and before enclosing the first surface of the substrate.