Korea IT News, Digitimes report that so called "blue filters" used in high-resolution BSI camera modules are in short supply. The "blue filters" are made of IR-absorbing material that can keep its IR stopping efficiency in wide acceptance angle typical for modern BSI sensors. Older FSI-based modules used multi-layer IR cut filters which are more sensitive to the angle. Korean makers OPTRONTEC, OPTRONTECH, Nanos and LMS have entered the market dominated by Japanese Asahi Glass and German Schott and drive the prices down.
Samsung Securities report gives more examples of BSI sensor artifacts when used with older IR cut filters: