Ford could have stopped at using phosphorous material for interior illumination of the fender storage area, but instead, the idea has snowballed. Ford also notes that “long persistent phosphor can emit amber colored light” and that “short persistent phosphor stops emitting light very quickly.”
The filing goes on to say that one type of phosphor could emit light in a first color while another could emit a different color. Thus, the patent suggests that a short persistent phosphor-painted area of the fender could act as an auxiliary turn signal. It seems a bit gimmicky and pointless, but in the future, we could have body panels that look green, for example, most of the time, and then have parts of them magically flash amber when turning. Sure, there’s no mention of added safety or increased reliability with such an invention, but Ford does mention aesthetics. Hopefully, if this tech ever becomes mainstream, it will be introduced in a way that doesn’t remind us of early Fast & Furious cars’ lighting.