Abstract: A mirror device (1) which can be simultaneously used for display purposes, based on e.g. an LCD display (5) with a polarizing mirror (6) placed in front of it. The polarizing mirror (2) has the characteristics that it does not disturb the transmission of the light from the display (5), but does reflect the light from outside the area of the screen. The polarizing mirror (2) is embedded in a conventional mirror (4,8).

Abstract: The invention relates to an instrument for surgery, in particular minimally invasive surgery. The instrument includes means for feeding back a force which is exerted on the working element of the instrument to the operating element. These means include at least a first force sensor for measuring the force which is exerted on the working element, a control unit and a first actuator. On the basis of a signal which originates from the first force sensor, the control unit controls at least the first actuator in order to control the operating element. Furthermore, the means preferably include a first position sensor for measuring a position of the working element with respect to the frame. The control unit advantageously determines an impedance which the working element is subject to as a result of the presence of a tissue or the like, on the basis of which impedance the control unit controls at least the first actuator.