| 摘要 |
1276885 Cathode ray storage tubes; semiconductor targets TEXAS INSTRUMENTS Inc 9 July 1969 [9 Sept 1968] 34599/69 Headings H1D and H1K An image storage device, in particular a scan converter, has a target 19 comprising a body 24 of N-type semi-conductor material having on one face an additional storage layer 28, for example of phosphorescent material, for receiving an image and in the other opposed face a number of discrete areas 26a, 26b of, for example, P-type semi-conductor material whose charge distribution is changed in correspondence to information of the received image which is indicated by the phosphor layer. A constant energy beam of electrons 31 from the read gun is scanned across the discrete P-type regions to form a corresponding uniform series of reverse biased depletion layers 32a, 32b. An intensity modulated beam of electrons 34 from the write gun or a light beam incident on phosphor layer 28 produces electron hole pairs, Fig. 5, in number corresponding to the intensity of the write beam, and the holes thus produced migrate to the P-type areas and are collected there to alter the reverse bias condition to a more positive charge condition. When scanned once more by the read beam 31 an alternating output signal detected by sensor 30 is produced by the target, whose value is dependent on the amount of charge required to reverse bias the individual P-type areas back to the reference level. The phosphors of layer 28 are chosen according to the length of delayed reading required. In an embodiment for use in radar screens, Fig. 7 (not shown) a low energy write beam used as described above to produce a persistant image is provided in conjunction with a high energy beam which penetrates the phosphor layer to produce a non- persistent image which may be used as a tag to identify persistent images. |
