Abstract: A 1D ultrasonic converter unit having at least three ultrasonic converters and a control unit for individually controlling each ultrasonic converter, wherein each ultrasonic converter has a housing, a piezoelectric body, and a sound decoupling layer for decoupling sound waves in a gaseous medium, is embedded in a common carrier structure, and emits and/or receives the same frequency between 20 kHz and 400 kHz. Each ultrasonic converter has one sound channel having an input opening associated with one sound decoupling layer, and an output opening. The output openings are arranged along a line, a distance between two adjacent output openings corresponds at most to the whole or half the wavelength of the sound frequency and is smaller than the distance of the input openings.

Abstract: A 1D ultrasonic converter unit having at least three ultrasonic converters and a control unit for individually controlling each ultrasonic converter, wherein each ultrasonic converter has a housing, a piezoelectric body, and a sound decoupling layer for decoupling sound waves in a gaseous medium, is embedded in a common carrier structure, and emits and/or receives the same frequency between 20 kHz and 400 kHz. The 1D ultrasonic converter unit one sound channel having an input opening associated with one sound decoupling layer, and an output opening. The output openings are arranged along a line, a distance between two adjacent output openings corresponds at most to the whole or half the wavelength of the sound frequency and is smaller than the distance of the input openings.

Abstract: The present invention relates to a flat display screen including a light-emitting source organized in a first array of strips generally parallel in a first direction, and at least one second opaque array, interposed between the light-emitting source and a display surface, and organized in a second direction generally non-perpendicular to the first direction, at least one of the arrays exhibiting, along an axis parallel to the general direction of the first array and whatever the position of this axis in a perpendicular direction, a constant proportion of transparent surface for an elementary pattern.

Abstract: A method for controlling a cathodoluminescent screen consists of providing regeneration steps during which at least a portion of the anodes is at a low voltage and the corresponding cathodes are biased to an emission state. When the screen is a microtip color screen, regeneration steps are provided between the operation steps and, during the regeneration steps, all the anodes are at a low voltage, the microtips and the gates being biased to an emission state.