Infrared heat rejection is one of the most critical parameters in evaluating the performance of window films. Due to differences in materials and manufacturing processes, window films exhibit distinct infrared absorption and reflection characteristics,
resulting in different test data when measured at different infrared wavelengths. Based on in-depth research into the spectral properties of window films, GUOOU has developed solar film testers using both 940nm and 1400nm infrared light sources,
offering single-wavelength as well as dual-wavelength solutions to meet a wide range of professional testing requirements.
Some window films achieve thermal insulation primarily by absorbing infrared energy through the addition of infrared-absorbing materials within the film structure. These absorption-type films show stronger infrared absorption characteristics around the 940nm wavelength.
Testing at this wavelength more accurately reflects their intended thermal insulation performance. In contrast, metal films and certain ceramic films are mainly manufactured using magnetron sputtering or similar processes,
forming multilayer structures that block heat by reflecting infrared radiation. These films typically exhibit stronger infrared rejection performance at the 1400nm wavelength, making this band more suitable for evaluating their true thermal insulation capability.
Regardless of whether a 940nm or 1400nm infrared light source is used, GUOOU window film testers measure the actual infrared rejection performance of the film within the corresponding wavelength band. Both measurement methods are based on optical principles and provide objective,
accurate, and repeatable data. When the same film is tested at different wavelengths, variations in infrared rejection values are normal and are determined by the film’s own spectral transmittance characteristics rather than by the accuracy of the instrument.
In practical testing, some window films may show similar infrared rejection performance at both 940nm and 1400nm, while others may display significant differences between the two wavelengths.These variations directly reflect differences in film structure and thermal insulation mechanisms and explain why a single-wavelength test cannot fully represent the performance of all window films.
For this reason, in addition to offering dedicated 940nm and 1400nm single-wavelength testers, GUOOU also provides dual-wavelength models that allow both bands to be measured within a single device, enabling a more comprehensive evaluation of infrared performance for both absorption-type and reflective-type window films.
By selecting the appropriate infrared wavelength or utilizing a dual-wavelength testing solution, window film performance can be evaluated in a more scientific and objective manner, avoiding misinterpretation caused by single-band measurements.
GUOOU remains committed to delivering reliable testing instruments based on accurate data and professional technology, helping users clearly and confidently understand the true infrared heat rejection performance of window films.
