Patent ID: 7891870

Claim:
A temperature sensor element, comprising: an elongated and columnar sintered body extending in an axial direction, said sintered body having an outer surface for exposure to a matter to be measured, said sintered body being formed by sintering insulating ceramic material, said sintered body having an outer circumference adhered to and held by an inner side of a metal flange member; a sensitive member embedded in the sintered body; and a signal output portion formed on a rear end side and on a further rear end side than a region covered by the flange member of the sintered body for outputting an electric signal received from the sensitive member to the outside, wherein the columnar sintered body comprises a tapered portion that has a plate-like shape relative to said sensitive end of said thermocouple, and said tapered portion has a cross-sectional area that is reduced towards a front end side of the sintered body in the axial direction; wherein the sensitive member is comprised of a thermocouple embedded in the tapered portion of the sintered body in a state that a detection end portion of the thermocouple is disposed in contact with said sintered body on a front end side of the sintered body in the axial direction, and wherein the sintered body is in contact with the detection end portion of the sensitive member and is a dense material which has gas impermeability in a region from the outer surface of the sintered body to the sensitive member the sintered body has a configuration that, in a cross section perpendicular to the axial direction, a cross-sectional area of a portion where the detection end portion of the thermocouple is embedded smaller than that of a portion where the signal output portion of the thermocouple is formed; and further, in the tapered portion of the sintered body, the portion where the detection end portion of the thermocouple is embedded assumes a plate-like shape in the cross-section perpendicular to the axial direction.