| 摘要 |
The invention relates generally to the treatment of skin using laser light, and more particularly to a non-invasive device and method for such treatment. During skin treatments, heating of the epidermis is undesired because it may cause discomfort for the person being treated, adverse skin reactions and unwanted changes in skin pigment. The invention provides a laser treatment beam having a first 22a and a second 22b beam region of non-zero light intensity disposed at a periphery of a transverse cross-section of the beam, and a third beam region 22c, arranged between the first 22a and the second 22b beam region, of lower light intensity than said non-zero light intensity. The treatment beam 22 exits the device 10 along its optical treatment axis 13. As the treatment beam 22 passes through an outer layer of the skin to the focal spot 25 along the optical treatment axis (13), the extent of the third beam region 22c is predetermined and/or controlled so as to provide a corresponding third skin region 23c in the outer skin layer 16, arranged between the first 23a and the second skin region 23b, and the lower light intensity of the third beam region is predetermined and/or controlled to provide a maximum temperature during a pulse of the laser treatment beam with in the third skin region 23c which is lower than the maximum temperatures during said pulse of the laser treatment beam within the first 23a and the second 23b skin region. The light source 20 is configured and arranged to provide, in use, a pulse duration of the pulse of the laser treatment beam which is longer than the thermal relaxation time of the first 23a and the second 23b skin region. By predetermining and/or controlling the dimensions of the third skin region 23c, a suitably dimensioned heat sink is created, centrally located within the region being heated by the laser treatment beam, and used to avoid temperature hot spots in the outer layers of the skin. |
