Patent attributes
In a hair styling device (20), a light emitting diode (33) is configured to deliver optical energy to hair, wherein an energy fluence of the optical energy is between 0.5 and 9 J/cm2, and more preferably between 1 and 5 J/cm2. The light emitting diode (33) is pulse-driven, and a pulse width of the optical energy is at least 50 ms. An output wavelength of the optical energy may be between 400 and 900 nm. The pulse width of the optical energy is preferably between 50 and 300 ms. The hair styling device (20) may comprise an optical shield (32) configured to block stray light during light exposure of the hair. An inner surface of the optical shield (32) may be reflective and/or may have a parabolic shape. The optical shield (32) may be movable between an open position in which a lock of hair can be placed in the hair styling device (20) while the optical energy is not applied, and a closed position in which light is prevented from escaping the hair styling device (20) while the optical energy is applied to the hair. The hair styling device may be a hair straightener having opposing first and second straightening surfaces, of which at least the first straightening surface comprises the light emitting diode (33), and at least the second straightening surface is arranged for reflecting light from the light emitting diode (33).
