US 5,823,680 AGranted

Temperature sensor

AssigneeNGK Insulators, Ltd.

InventorsNobuhide Kato, Nobukazu Ikoma

Life of this patent

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Abstract

A temperature sensor includes a ceramic substrate, and a sensing resistor containing platinum is embedded in the ceramic substrate. Electric current can be applied to the sensing resistor through the lead. The voltage of the sensing resistor can be detected through the second lead. Another resistor for dividing voltage is electrically connected to the sensing resistor, the resistor is trimmed by laser irradiation so as to adjust its electrical resistance value such that upon applying electric current having a certain value onto the sensing resistor an output voltage having a predetermined value is generated. Heat generated by the laser irradiation to the resistor does not affect an electrical resistance value of the resistor as much as that of the sensing resistor, thereby improving precision of the temperature sensor. The sensing resistor avoids contact with the atmosphere.

Claims16

Dependent claims

A temperature sensor comprising:

a ceramic substrate having a first end and a second end:
a sensing resistor, being embedded in said ceramic substrate at said first end, having a positive temperature coefficient of resistance;
a first pair of leads connected to said sensing resistor, wherein electric current can be applied to said sensing resistor through said first pair of leads;
a second pair of leads connected to said sensing resistor;
and
a voltage-dividing resistor disposed at said second end of said ceramic substrate, and electrically connected to said sensing resistor by means of said second pair of leads, said voltage-dividing resistor having an electrical resistance value such that upon applying electric current having a certain fixed value to said sensing resistor, a voltage, which can be detected between said second pair of leads and is indicative of a change in temperature of the sensing resistor, is generated across said sensing resistor, said voltage being divided so that an output voltage between one of said second pair of leads and at least a portion of said voltage dividing resistor is adjusted to be a predetermined value.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/815,431Filed 11 Mar 1997 · continuation
Priority: JP 5-32930627 Dec 1993
Granted: 20 Oct 1998
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G01K 15/00
Testing or calibrating of thermometers
G01K 7/183
The element being a linear resistance, e.g. platinum resistance thermometer: characterised by the use of the resistive element
G01K 13/02
Thermometers specially adapted for specific purposes: for measuring temperature of moving fluids or granular materials capable of flow
G01K 2205/04
Application of thermometers in motors, e.g. of a vehicle: for measuring exhaust gas temperature