LIOB BASED HAIR CUTTING DEVICE

摘要

A laser-based hair cutting device (10) is provided, which device (10) comprises a laser source (18), an optically transparent exit window (15) and optical elements (11, 12, 13, 14) The laser source (18) provides an incident light beam (21) for cutting a hair (22) above and near a skin surface by laser-induced optical breakdown (LIOB) of the hair (22) in a focal position of the light beam (21). The optically transparent exit window has an external exit surface (15) for allowing the incident light beam (21) to leave the device. The optical elements (11, 12, 13, 14) focus the incident light beam (21) in the focal position at a working distance from the exit surface (15). The laser source (18) and the optical elements are arranged and configured such that the working distance is at least (I) wherein NA is a numerical aperture of the incident light beam leaving the device (10), Ep is a pulse energy (J) of the incident light beam (21), Fthresh is a fluence threshold (J/m2) of the exit surface, M2 is a beam quality of the incident light beam (21) and λ is a wavelength (m) of the incident light beam (21).;1πNA22EpNA2πFthresh-M2λ2(1)

主权项

1. A laser-based hair cutting device comprising:
a laser source for providing an incident light beam for cutting a hair above and near a skin surface by laser-induced optical breakdown (LIOB) of the hair in a focal position of the light beam, an optically transparent exit window with an external exit surface for allowing the incident light beam to leave the device, optical elements for focusing the incident light beam in the focal position at a working distance from the exit surface, wherein the laser source and the optical elements are arranged and configured such that the working distance is at least1πNA22EpNA2πFthresh-M2λ2wherein NA is a numerical aperture of the incident light beam leaving the device, Ep is a pulse energy (J) of the incident light beam, Fthresh is a fluence threshold (J/m2) of the exit surface, M2 is a beam quality of the incident light beam and λ is a wavelength (m) of the incident light beam.