Thermometer using differential temperature measurements

摘要

The thermometer using differential temperature measurements utilizes a pair of adjacent temperature sensors in order to measure the temperature of a common surface over a pre-selected period of time. The thermometer includes a housing and first and second thermistors mounted adjacent one another on the housing. The first and second thermistors are positioned against the surface, which can be a body part (for oral, rectal or axial body temperature measurements) or can be any other desired surface for which a spot check temperature reading is desired. A programmable current source pre-heats the second thermistor to a pre-selected temperature, while the first thermistor is initially at room temperature. A controller inside the housing causes both the first and second thermistors to take instantaneous temperature measurements of the surface at two successive times. The controller linearizes the measurements to predict the temperature of the surface, which is then displayed to the user.

主权项

1. A thermometer using differential temperature measurements, comprising:
a housing having a sensor area; first and second thermistors mounted in adjacent spaced relation in the sensor area on the housing, said first and second thermistors being adapted for positioning against a surface; a programmable current source for pre-heating said second thermistor to a pre-selected temperature, wherein said first thermistor is initially at a room temperature; means for measuring a temperature bC with said first thermistor at a first time t0; means for measuring a temperature bH with said second thermistor at the first time t0; means for measuring a temperature bC1 with said first thermistor at a second time t1; means for measuring a temperature bH1 with said second thermistor at the second time t1; means for calculating a slope aC of a linearized temperature measurement curve associated with said first thermistor asaC=bC-bC⁢⁢1t0-t1; means for calculating a slope aH of a linearized temperature measurement curve associated with said second thermistor asaH=bH-bH⁢⁢1t0-t1; means for calculating a temperature BT of the surface asBT=aC·(bH-bCaC+aH)+bC;and
a display for displaying the temperature BT.