Infrared (IR) sensors or thermometers use infrared radiation to measure the temperature of objects without direct contact. These non-contact temperature sensors detect the heat emitted or reflected by the object and convert it into a temperature reading. Infrared thermometers are widely used in various applications, including industrial, medical, automotive, and home use. There are several types of infrared thermometers based on their functionality and application:

1. Spot Infrared Thermometers: These are the most common type of infrared thermometers. They measure the temperature of a specific spot on the object being measured. They are handheld devices that are pointed at the object, and the temperature reading is displayed on a digital screen.

2. Infrared Scanning Thermometers: Also known as infrared scanning guns, these thermometers can measure the temperature of a larger area or scan a surface to detect temperature variations. They are commonly used in industrial applications for temperature mapping and monitoring.

3. Infrared Thermal Imaging Cameras: These advanced devices use infrared sensors to capture thermal images of surfaces and objects. They provide a visual representation of temperature variations and are used in various applications, including building inspections, electrical troubleshooting, and industrial process monitoring.

4. Infrared Ear Thermometers: These thermometers are designed for medical use and are commonly used to measure body temperature through the ear canal. They provide quick and non-invasive temperature readings.

5. Infrared Forehead Thermometers: Similar to ear thermometers, infrared forehead thermometers are used in medical settings to measure body temperature quickly and without contact.

6. Infrared Food Thermometers: These thermometers are used in food preparation and cooking to measure the temperature of food items without physically touching them.

7. Infrared Fever Screening Systems: These systems are used for mass screening of individuals to detect elevated body temperatures, often used at entrances to public places or during disease outbreaks.

Infrared thermometers are valuable tools for temperature measurements in situations where direct contact is not practical or safe, or where rapid temperature readings are required. The type of infrared thermometer chosen depends on the specific application, temperature range, accuracy requirements, and the size of the area or object to be measured.