I've always seen that all the old model remotes that is used in DVD players or TVs, it emits electromagnetic waves, having wavelength somewhere in the Infrared region. But when my phone's average quality camera (Moto E) is held between the emitter and my eyes, it converts the infrared into visible ones and shows a whitish purple colour. I don't know why always the purple is shown. I'll be very happy if you explain this to me. Thank you.
The comments are on the right track. First thing: the R,G,B filters in a standard digital camera each pass some IR light, i.e. they're not low-frequency blocking. Usually cameras add an IR-blocking filter on top of the color grid because of this. An example RGB filter from FujiFilm is shown in this picture:
which is from somwhere near here You can see the Blue sensitivity in the Near-IR.
EDIT: Just to clarify: the three curves are for different thicknesses of the color filters, not (0.7, 0.9, 1.1 $\mu m$) wavelengths Camera manufacturers are usually unwilling to release their color filter specifications, unfortunately. You might get lucky if you Google around for your particular model.