NIR band-pass filters for CMOS image sensors constructed with NIR absorbing dyes and plasmonic nanoparticles

Abstract

Two NIR band-pass filters for CMOS image sensors are developed by incorporating NIR absorption dye and silver nanodisks simultaneously in a transparent polymer, one of which blocks the NIR near the wavelength of 750 nm and the other near 950 nm. They offer low NIR transmittance while maintaining high visible light transparency even at a thin film thickness of 500 nm. By superimposing the proposed NIR band-pass filters, an NIR cutoff filter with a thickness of 1 µm is formed that shields the NIR at wavelengths longer than 680 nm while remaining transparent in the visible range.