An infrared irradiance meter with a pyroelectric detector, which is an instrument to estimate a heater, an luminaire utilizing infrared radiation and a lighting system, has been developed. Its characteristics are as follows:(1) it is compact and portable, (2) it is hardly influenced by a change of temperature and a vibration, (3) it has an approximate flat spectral responsivity in wide infrared region, (4) the detectivity is better than 1mW/cm2, (5) the response time is 0.7 sec. Actually infrared radiation of several radiation sources are measured by the fabricated instrument, it is recognized that the instrument is very useful for the measurement of infrared radiation. Finally, it is discussed that the absorptions of air and the detector window influence the response of the instrument, and then the correcting expression for the absorptions is derived.
