Infrared Detector

The infrared detector is a core sensing element used in infrared pyrometers and other optical measurement systems. It captures infrared radiation emitted by a target object and transforms it into a measurable electrical signal, which can be processed to determine temperature or detect presence. The detector operates on either the photoelectric effect (in semiconductor types such as silicon, germanium, or InGaAs) or the thermal effect (in pyroelectric crystals like lithium tantalate). When infrared radiation strikes the detector, its electrical properties—such as resistance, voltage, or current—change proportionally to the radiation intensity. This change is then converted into a signal that can be amplified and interpreted by associated electronics. The detector's performance is characterized by parameters including spectral range (typically 1–14 μm), detectivity (1e8–1e10 cm·Hz^0.5/W), response time (1–100 ns), and operating temperature (-40 to 85 °C). It is available in various package types (TO-5 to TO-8) and active areas (0.1–10 mm²), with options for field of view (60–120°), supply voltage (3.3–5 V DC), and power consumption (10–500 mW). The detector is designed for integration into industrial temperature measurement systems, where it must be selected based on the target's temperature range, spectral characteristics, and response speed requirements. It is important to verify model-specific values and standards with the legal manufacturer or supplier, as the listed ranges are general references. The detector is a passive component and does not include signal processing or display functions; it requires external circuitry for operation. Proper handling and installation are necessary to avoid damage from electrostatic discharge or excessive heat. Regular calibration and maintenance are recommended to ensure accurate readings over time.

The detector absorbs incident infrared radiation, causing a change in its electrical properties based on the photoelectric or thermal effect. In semiconductor detectors, photons with sufficient energy generate electron-hole pairs, altering conductivity. In pyroelectric detectors, temperature changes alter the crystal's polarization, generating a voltage. This change is proportional to the radiation intensity and is converted into an electrical signal for further processing.