Abstract: A flat screen field emission cathode is disclosed including microtips individually protected by means of a series electrical coupling with a dipole consisting of a depletion mode field effect transistor. The current-voltage characteristic of such a dipole is not linear. These dipoles can be obtained such that the protection threshold and current emission level, and therefore the brilliance of the screen, can be altered globally (on all tips at once) solely by acting on the biasing of the substrate common to these dipoles, or groups of dipoles.

Abstract: A method for manufacturing a fluorescent display screen cathode including microtips, comprises a supporting plate bearing cathode conductors in meshed columns, a resistive layer bearing microtips, an insulating layer and a grid conductive layer in rows. The method comprises the step of simultaneously etching the three upper grid layer, insulating layer and resistive layer according to a single perforated pattern defining both the grid rows and the access resistance to the microtips through the resistive layer.

Abstract: A process is disclosed for positioning spacer beads on a plate of a flat display screen formed by two adjacent plates constituting a flat air-tight chamber. The method includes providing a hollow needle mounted on a mobile head which is connected to a vacuum/overpressure system. The hollow needle sucks a bead from a bead tank, applies the bead onto a plate covered with an adhesive material to adhere adhesive onto a section of the bead, then removes the bead from the plate. Finally, the needle deposits the bead onto one of the two adjacent plates.

Abstract: A method for assembling a spaced flat panel display screen having a first plate and second plate, each with an internal facing surface that are opposing comprises the steps of positioning spacers on the internal facing surface of the first plate, positioning the second plate so that the internal facing surface of the second plate contacts the spacers, heating the spacers to a temperature causing soldering of the spacers to the plates, pulling the first and second plates apart to stretch the spacers to a predetermined distance, and cooling the spacers.

Abstract: A method for producing microdot emitting cathodes on silicon for compact flat screens, and the products obtained by means of said method, are disclosed. According to the method, the emitting cathodes are made from a basic monolithic silicon substrate (1) consisting of a thick wafer (at least 300 microns) or a thin film a few microns thick on an insulating substrate (alumina or glass), the silicon film being "active" in both cases. The method is useful in the field of flat display screens based on the physical phenomenon of cathodoluminescence and field effect electron emission, and in all industrial sectors using compact display screens, e.g. video camera viewfinders, calculators, monitoring devices of all kinds, vehicles, watches and clocks, etc.

Abstract: A short pumping stem for flat display screens, more particularly for microtip flat display screens, generally adaptable to flat display screens constituted by a vacuum chamber, includes, before closure, an exhaust tube whose lower portion is integral with the middle portion of an upper concave wall of a cylindric portion having a diameter larger than the diameter of the tube.