Non-contact infrared thermometer

A temperature measurement method for using a forehead thermometer to measure a temperature of a target area of an object to be measured, the temperature measurement method comprising the steps of:

• providing the forehead thermometer that includes an infrared sensor for measuring a magnitude of infrared rays radiated from the target area of the object to be measured, a time-of-flight sensor measuring an actual temperature measurement distance from the target area, a microprocessor electrically connected to the infrared sensor and the time-of-flight sensor respectively, a storage electrically connected to the microprocessor and configured to store a predetermined temperature measurement distance, and an alignment unit having a light-emitting element and an optical element, the light-emitting element emitting light which passes through the optical element to project an alignment mark on the target area, wherein the target area is at a center of the forehead, or skin near temples or on arteries;
• activating the forehead thermometer;
• activating the alignment unit to project the alignment mark on the target area;
• confirming that an actual temperature measurement distance is equal to the predetermined temperature measurement distance;
• confirming that the forehead thermometer is straightly facing the target area, based on the angle between an optical axis of the alignment unit and a normal line to the surface of the target area is less than or equal to a predetermined angle and the distance relative to the target area determined from the size of the projected alignment mark is equal to the predetermined temperature measurement distance;
• and
• measuring the temperature of the target area of the object to be measured with the infrared sensor.