Infrared SensorsBasics

This presents an overview of infrared sensors in addition to their basic characteristics, features, principles of operation, and other basic technical information.

What is a pyroelectric infrared sensor?

A pyroelectric infrared sensor detects infrared by applying the pyroelectric effect of pyroelectric ceramics, which are a type of piezoelectric ceramics.
At Murata, we have developed high-performance and high-reliability pyroelectric infrared sensors based on ceramic technologies independently cultivated over many years.

Types and comparisons of infrared sensors

Infrared sensors can be largely divided into "thermal" and "quantum" types based on their operational principles.
Pyroelectric infrared sensors are categorized as "thermal" sensors.
Moreover, even sensors which use the same infrared waves have different types depending on the infrared wavelength used.

What you can and cannot do with infrared sensors

Pyroelectric infrared sensors are the optimal sensors for detecting people, but they cannot detect still objects.

What is the Fresnel lens used in infrared sensors?

The movement of people far away cannot be detected with only a sensor.
Therefore, please use a lens which plays a role in collecting the infrared rays together with the sensor.

Operational principles

When the infrared rays enter the sensor, the sensor section heats up, and a temperature change occurs.
That change is extracted as an electrical signal and used as an output signal.