Abstract: The present invention relates to a skin treatment device (1, 1?). The device comprises in a housing a source of radiation (13), that is emittable through an exit opening in the housing. It further comprises a plurality of skin presence sensors (43, 63) that are able to measure the presence of skin (7) at their respective positions, and a control unit (37). The control unit (37) is constructed to determine a covered part of the exit opening (15) from measurement signals of the skin presence sensors, and to restrict emission of the radiation (13) to the covered part of the exit opening (15), e.g. by modifying the control of a radiation beam manipulator (11), or by controlling radiation blocking means, such as blinds, in the exit opening (15). The invention provides a more efficient and yet safe treatment device (1, 1?), since a larger exit opening (15) may be selected, while unwanted emission of radiation (13) through uncovered parts of the exit opening (15) is yet prevented.

Abstract: The invention relates to a device (1) for the treatment of skin (13) by means of a radiation beam (5). The device comprises a radiation source (9) for generating the radiation beam, a beam exit window (15), an optical detecting system (31) for determining a target position (22) of the radiation beam relative to the skin, and a beam manipulator (17) for positioning the radiation beam in the target position. The radiation beam and the detecting system have a first optical axis (45) and a second optical axis (47), respectively. According to the invention, seen from the radiation source (9) towards the beam exit window (15), the first and the second optical axis (45, 47) coincide starting at a position (S) between the radiation source and the beam manipulator (17).

Abstract: The invention relates to a device (1) for shortening hairs (3), in particular growing from human skin (5). The device (1) has a laser source (7) for generating a laser beam (9) during a predetermined pulse time, an optical system (15) for focusing the laser beam into a focal spot (25), and a laser beam manipulator (17) for positioning the focal spot in a target position. According to the invention, a dimension of the focal spot (25) and a power of the generated laser beam (9) are such that, in the focal spot (25), the laser beam has a power density which is above a characteristic threshold value for hair tissue above which, for the predetermined pulse time, a laser induced optical breakdown (LIOB) phenomenon occurs in the hair tissue. The LIOB phenomenon results in a number of mechanical effects in the hair tissue, such as cavitation and the generation of shock waves, which damage the hair (3) in positions surrounding the position in which the LIOB phenomenon occurs.

Abstract: The invention relates to a device (1) for treating human skin by means of radiation. The device comprises a housing (3) with a radiation exit opening (13). A radiation source (9) is accommodated in the housing. Radiation generated by the radiation source propagates from the radiation source towards the radiation exit opening via a radiation path (15) comprising a radiation filter having a predetermined transmission spectrum. According to the invention the radiation filter comprises a reflecting surface (23) via which the radiation propagating along the radiation path (15) is reflected. The reflecting surface has a coating which provides the reflecting surface with a reflection spectrum substantially matching the predetermined transmission spectrum. An advantage is that the reflection surface can be optimally and uniformly cooled, so that the heat generated as a result of the absorption of part of the radiation by the radiation filter can be effectively transmitted to a cooling system (25) of the device (1).