1. Field of the Invention
The present invention relates to a support device controlled in dependence on the movement of a helmet with respect to a surrounding structure, the helmet being worn on an operator's head. More specifically, the invention permits control of the device in dependence on movements of the head which are exerted within a well-defined volume, the device being thus used for supporting equipment normally mounted on the helmet and for relieving the operator of the corresponding load.
2. Description of the Prior Art
The use of the invention is more particularly contemplated in the field of avionics for solving the problem of video image display in a large field of view and with high resolution. In fact, the pilot on board a fighter aircraft is installed within a cockpit of small size and in most cases in a recumbent position, which hardly facilitates reading of instruments on the aircraft instrument panel. For example, a cathode-ray-tube (CRT) screen indicator providing an elaborate video display is therefore always perceived at a small angle, with the result that its effectiveness is impaired. The collimated display device mounted on a helmet restores a certain degree of visual comfort for the pilot but remains limited to small fields or, in the case of larger fields, to a medium resolution corresponding, for example, to an image of 250 points per line and of 250 lines. The installation on a helmet of a large-field display having high resolution (namely a resolution which is higher than 1000 points per line) results in prohibitive weight which is not compatible with accelerations of up to approximately 8 g for which the aircraft is designed.
The object of the invention is to overcome these disadvantages and limitations by making use of a support device which is mechanically decoupled from the pilot's helmet, which is placed at a short distance from said helmet in a predetermined position and which is controlled in dependence on the movements of the pilot's head and therefore of the pilot's helmet. This support device is thus capable of performing the function of the helmet and replaces this latter for the purpose of carrying the necessary electro-optical equipment. In particular, it will be possible to install a large-field high-resolution display system on this support device. The pilot is freed from the weight of these equipment elements and is thus permitted to move his head freely.