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 cathode includes microtips for flat display screens, of the type including cathode conductors, between a substrate and a gate, the gate including holes inside meshes defined by the cathode conductors. An insulating layer, including wells facing the holes, is interposed between the cathode conductors and the gate. Microtips are deposited in the wells, onto a resistive layer. The cathode conductors are deposited over the resistive layer and are coated with an auxiliary insulating layer.

Abstract: A microtip cathode for flat panel display screens has a constant access resistance and includes a substrate (10), a resistive layer (19), at least one cathode conductor (13), an insulating layer (16), and a control gate (3). The microtip cathode further includes an auxiliary insulating layer (18) disposed between the cathode conductor (13) and the insulating layer (16) to suppress needle hole effects in the insulating layer (16).

Abstract: A flat panel display includes cathode columns with microtips for emitting electrons, arranged in gate rows, and an anode provided with phosphor elements arranged in groups of juxtaposed strips, electrically insulated one from the other. The intersection of a gate row and of a cathode column defines a pixel of the display. The groups of anode strips are electrically connected to form two networks. A first network includes groups of strips of odd rank, while the second network includes the groups of strips of even rank. The flat panel display further includes an electronic control system adapted to sequentially address the groups of odd rank, and even rank, respectively.

Abstract: A device for sputtering a metallic material on a plate comprises a vacuum chamber provided with a linear conveyor carrying at least one plate, the plate surface to be processed being turned downward. At least two sputtering sources are disposed under the conveyor, perpendicularly to its moving direction. Each source is associated with a collimator. The sputtering sources and their associated collimators are disposed to coat the whole width of the plate.

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 device and a process for the control of a microtip fluorescent screen or display formed from pixels arranged in accordance with L rows and M columns of images able to have a discrete number of Q grey tones, in which the column voltage values are chosen in a strictly increasing sequence of N+1 values such that the row selection time being subdivided into S equal time intervals .DELTA.t, each voltage value is applied an integral number of times .DELTA.t, (N.times.S)+1 representing the number of grey levels, with N.gtoreq.2 and S.gtoreq.2. During a row selection time, the corresponding column voltage assumes a first value Va during a certain number of time intervals .DELTA.t, then during the remaining time intervals it additionally has a second value Vb following onto the first in the sequence of N voltages.

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.