I want to know if it is possible to make a red L.E.D. display appear a different color, at least theoretically, but ultimately for a D.I.Y project.
Based on answers to this question (How do color filters placed in front of a light source,change the color of light that passes through?), white leds use phosphors to emit some other frequencies than the base LED.
Is it possible to use that principle in a film like that can be placed on top of a display to change its appearance?
Is there another approach that can yield similar results?
Is there a material accessible to public to easily (and cheaply) make such filter?
In case it matters for the question, I have a cheap mp3 module that has a bright red display (similar to 7-segment LED) that I use in my car that I'd like to make less outstanding against the green lights of my car's dashboard. I've have tried some plastic films but all I've achieved is to reduce the brightness.
As far as I understand, such cheap display would have LEDs that emit a single frequency, so a simple colored filter won't change apparent color, only absorb part of the red light.