Tanning disc

 作者:闻健黉     |      日期:2019-03-08 01:12:00
By Barry Fox Its days may be numbered, but the floppy disc is about to get a place in the Sun. Agfa-Gevaert of Belgium is modifying the humble disc to tell sunbathers if their tanning sessions are too long (EP 892 283). The altered floppy has a sheet coated with a phosphor, barium fluorobromide, which is excited by ultraviolet rays. When you sunbathe, you open the disc’s shutter so the rays strike the sheet. A reader, based on a modified floppy drive, then uses a helium neon laser to make the excited phosphor glow. By measuring the fluorescence, it can work out how much UV struck the disc. Trouble is,