Skin treatment device with radiation emission protection

The present invention relates to a skin treatment device (, F). The device comprises a radiation source in a housing, such that radiation can be emitted through an exit opening in the housing. It further comprises at least one skin presence sensor capable of measuring the presence of skin in a number of respective positions, and a control unit. The control unit is constructed to determine a covered portion of the exit opening from a measurement signal of the skin presence sensor and to restrict emission of the radiation to the covered portion of the exit opening, e.g. by modifying the control of a radiation beam manipulator, or by controlling radiation-blocking means, such as blinds, in the exit opening. The invention provides a more efficient and yet safe treatment device, since a larger exit opening can be selected, while unwanted emission of radiation through uncovered portions of the exit opening is still prevented.