The method of determining of optical transparency of polyimide films of various thicknesses using high-resolution spectrometers

The article presents a method for determining the optical transparency of polyimide films used in the manufacture of fl exible electronics devices by laser carbonization. Information about the optical transparency of polyimide films in the visible and near-infrared ranges of the spectrum allows you to choose the optimal mode of laser carbonization. Using a calibrated radiation source and small-sized high-resolution spectrometers, data on the intensity of transmitted radiation through polyimide films of various thicknesses at several thousand wavelengths in the visible and near-infrared spectral ranges were obtained. Two operating wavelengths of solid–state lasers were selected from the obtained data array: 694.3 nm (ruby laser) and 1064 nm (neodymium-doped yttrium aluminum garnet laser, Nd:YAG). The dependences of the transmission coefficients of polyimide films with a thickness of 100, 200 and 300 microns on these wavelengths are constructed. It is shown that similar dependences can be constructed for all types of lasers emitting in the specified spectral ranges. Knowledge of the transmission coefficient of polyimide at various wavelengths will help to more accurately investigate and understand the essence of the physico-chemical processes occurring in the material when exposed to laser radiation of a certain wavelength. The proposed method for determining the optical transparency of polyimide films can be used to find the transmission intensity of any translucent materials used in laser and other technologies.

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