Method of erasing information in a scan converter storage tube

In a scan converter storage tube of the type having an electron gun of an electrostatic focus and deflection variety for generating a modulated or unmodulated electron beam, the electron gun including a cathode and a field mesh electrode, and a storage target to be scanned by the electron beam from the electron gun, the storage target including a substrate fabricated from a single crystal of insulating material, the substrate having a storage surface which is disposed opposite to the field mesh electrode of the electron gun and which has formed thereon a collector electrode having a plurality of regularly patterned openings formed therein, a method of erasing information from the storage target which comprises:

• (a) setting the potential (Vc) of the collector electrode lower than the potential (Vm) of the field mesh electrode and at such a value that the potential (Vs) of the storage surface with respect to the potential (Vk) of the cathode is made higher than a first crossover potential (Vl) at which the secondary emission ratio of the substrate first becomes unity;
• (b) causing the electron gun to scan the storage surface of the substrate with the unmodulated electron beam while the potential (Vc) of the collector electrode is set as in step (a);
• (c) setting the potential (Vc) of the collector electrode lower than the potential (Vk) of the cathode and at such a value that the potential (Vs) of the storage surface with respect to the potential (Vk) of the cathode is made lower than the first crossover potential (Vl) of the substrate;
• (d) causing the electron gun to scan the storage surface of the substrate with the unmodulated electron beam while the potential (Vc) of the collector electrode is set as in step (c);
• (e) increasing the potential (Vc) of the collector electrode to such an extent that the potential (Vs) of the storage surface with respect to the potential (Vk) of the cathode remains less than the first crossover potential of the substrate;
• (f) causing the electron gun to scan the storage surface of the substrate with the unmodulated electron beam after the potential (Vc) of the collector electrode is increased as in step (e);
• and
• (g) repeating the steps (e) and (f) until the potential (Vc) of the collector electrode becomes higher than the potential (Vk) of the cathode.

In a scan converter storage tube of the type having an electron gun of an electrostatic focus and deflection variety for generating a modulated or unmodulated electron beam, the electron gun including a cathode and a field mesh electrode, and a storage target to be scanned by the electron beam from the electron gun, the storage target including a substrate fabricated from a single crystal of insulating material, the substrate having a storage surface which is disposed opposite to the field mesh electrode of the electron gun and which has formed thereon a collector electrode having a plurality of regularly patterned openings formed therein, a method of erasing information from the storage target which comprises:

• (a) setting the potential (Vc) of the collector electrode lower than the potential (Vm) of the field mesh electrode and at such a value that the potential (Vs) of the storage surface with respect to the potential (Vk) of the cathode is made higher than a first crossover potential (Vl) at which the secondary emission ratio of the substrate first becomes unity;
• (b) causing the electron gun to scan the storage surface of the substrate with the unmodulated electron beam while the potential (Vc) of the collector electrode is set as in step (a);
• (c) making the potential (Vs) of the storage surface higher than the potential (Vk) of the cathode and, with respect to the potential (Vk) of the cathode, lower than the first crossover potential (Vl) by setting the potential (Vc) of the collector electrode with respect to the potential (Vk) of the cathode lower than the first crossover potential (Vl) and by setting the potential (Vm) of the field mesh electrode lower than its value in steps (a) and (b);
• and
• (d) causing the electron gun to scan the storage surface of the substrate with the unmodulated electron beam while the potential (Vc) of the collector electrode and the potential (Vm) of the field mesh electrode are set as in step (c).

In a scan converter storage tube of the type having an electron gun of an electrostatic focus and deflection variety for generating a modulated or unmodulated electron beam, the electron gun including a cathode and a field mesh electrode, and a storage target to be scanned by the electron beam from the electron gun, the storage target including a substrate fabricated from a single crystal of insulating material, the substrate having two opposite surfaces one of which is a storage surface disposed opposite to the field mesh electrode of the electron gun, the storage target further including a collector electrode on the storage surface of the substrate and a backing electrode on the other surface of the substrate, the collector electrode having a plurality of regularly patterned openings formed therein, a method of erasing information from the storage target which comprises:

• (a) setting the potential (Vc) of the collector electrode lower than the potential (Vm) of the field mesh electrode and at such a value that the potential (Vs) of the storage surface with respect to the potential (Vk) of the cathode is made higher than a first crossover potential (Vl) at which the secondary emission ratio of the substrate first becomes unity;
• (b) causing the electron gun to scan the storage surface of the substrate with the unmodulated electron beam while the potential (Vc) of the collector electrode is set as in step (a);
• (c) making the potential (Vs) of the storage surface higher than the potential (Vk) of the cathode and, with respect to the potential (Vk) of the cathode, lower than the first crossover potential (Vl) by setting the potential (Vc) of the collector electrode with respect to the potential (Vk) of the cathode lower than the first crossover potential (Vl) and by setting the potential (Vb) of the backing electrode lower than its value in steps (a) and (b);
• and
• (d) causing the electron gun to scan the storage surface of the substrate with the unmodulated electron beam while the potential (Vc) of the collector electrode and the potential (Vb) of the backing electrode are set as in step (c).