Electron beam image recorder

A new electron beam recording medium is reported. The medium is well suited for use in a high resolution recorder with near-real-time display capability. The development time can be less than 1 s. Black-on-white images are produced on the opaque tape with a contrast of 15:1 by exposure with 1 × 10¹¹electrons/cm²for a peak density of 1.3. The resolution of the medium exceeds 500 line pairs/mm, and the granularity is very low. Another feature of the medium allows the recorded information to be read out directly from the tape with a scanning electron beam. The latent image is produced by a process termed nucleation. Electron bombardment of the tape produces nucleation sites which are extremely favorable deposition sites for metal vapor atoms. Development takes place in the vacuum, immediately after electron beam recording, by selectively depositing a thin metal film which forms the image. The developed image is permanent and does not degrade under further electron beam bombardment or high intensity projection lamps. Recordings of 945-line television with a 20 MHz bandwidth have been made with an electron beam recorder, which was constructed for evaluating the media. An opaque projector was also constructed for projecting 35 mm images from the tape to a large screen display.