A direct viewing bistable storage tube is described in which post-deflection acceleration of the writing electron beam is employed to provide a high writing rate during conventional nonstorage operation without affecting the storage operation by separating the flood electrons from the high acceleration field in space or time. This is achieved either by positioning the post-deflection acceleration electrode between the output of the beam deflection means and the flood gun so that the low velocity flood electrons do not pass through the post-deflection acceleration field, or by adjusting the voltage on the acceleration electrode to eliminate the post-deflection acceleration field during storage. In addition, the first-mentioned type of storage tube is provided with an improved write-through operation using a reduced current writing beam due to the post-deflection acceleration so that a nonstored image of high brightness is produced simultaneously with a stored image on the same area of a phosphor storage dielectric in such tube.
A method and apparatus is described for providing non-storage electron multiplier operation of transmission storage tubes and other cathode ray tubes employing a transmission mesh target and a separate phosphor screen spaced therefrom. The improved operation is achieved by bombarding the dielectric layer on the mesh target electrode with low velocity flood electrons to charge such dielectric to a negative voltage with respect to the target electrode, thereafter bombarding the charged dielectric with a beam of high velocity writing electrons having energies greater than the first crossover potential to cause secondary electron emission at a greater than unity ratio to provide electron multiplication and attracting the secondary electrons through the mesh openings of the target electrode to the phosphor screen. The flood electron gun may be turned off during writing so that the flood electrons do not strike the phosphor screen in order to provide better image contrast. This electron multiplication increases the current of the electron beam striking the phosphor screen and thereby increases the maximum nonstored writing speed and the brightness of the light image.
A field emission device includes a substrate in which a well has been formed. Carbon fibers with a high aspect ratio are deposited within the well, wherein the well is sufficiently deep so that axes of a large number of the carbon fibers are substantially coaxial with a long axis of the well. A conductive anode is positioned relative to the substrate so that an electric potential applied between the conductive anode and the substrate causes an emission of electrons from the carbon fibers towards the conductive anode.
