Interface unit between a user and an electronic device

Interface unit between a user and an electronic device comprising a control logic and a rectangular cathode screen with a scanning facility where a luminous spot scans the screen according to a pre-determined scanning cycle, wherein the unit has

• a control box including:
• at least two lighting sensors adapted to the scanning of the screen by the luminous spot:
• a lighting sensor D1 which has a detection field comprising at least the upper left section of the screen;
• a lighting sensor D2 which has a detection field limited to a reduced zone Z of the screen;
• a wide-band amplifier and a high-pass filter for each of the lighting
• means of detection of the appearance of the luminous spot in the detection field of each of the sensors in order to generate a pre-determined logical signal;
• means of logical and arithmetical processing of the logical signals in order to calculate the position of the target zone Z on the screen at least on the basis of firstly the instant of appearance of the logical signal corresponding to the lighting sensor D1 whose detection field comprises at least the upper left section of the screen and which corresponds to the start of image-scanning, and secondly the instant of appearance of the logical signal corresponding to the lighting sensor D2 whose detection field is reduced and which corresponds to the passage of the luminous spot in front of the target zone Z;
• a transmission chain from the box towards the electronic device, the device having a logic adapted in order to be modified by the information received,
• and wherein the control box is placed at a distance from the cathode screen.