EL Panels have been used as display backlights in consumer and professional electronic equipment for more than 30 years.
They have proven to be very reliable but if the unit is still being used after more than 10,000 hours of lit display then these will start to fade.
As these units are often decades old, the manufacturer has often discontinued the product and users then discover that replacement screens for their beloved hardware are often expensive or impossible to find.
Instead of replacing the entire screen, an inexpensive EL Panel back light replacement can be inserted instead.