Storage tube

The Direct -View Storage Tube ( DVst ) ( " Direct Imaging storage tube " ) or Direktadressierröhre is a screen type that was developed in the late 1960s. DVSTs were in contrast to conventional vector screens display a graphic without a periodic repainting was necessary.

Art and meaning

The DVst based on the cathode ray tube, but supplemented by a fine metal mesh which has been coated with a dielectric. It serves as a storage device and is located behind the phosphor screen. The primary electron gun draws the image by electrons pushes out the memory device and so leaves behind a pattern of the positive charges. A second electron gun ( Flood Gun) outputs a constant current of low-energy electrons which are attracted to the memory device, and pass through only by the positively charged areas, to finally strike the phosphor screen. If an image is drawn once, it stays on the screen for several minutes visible until it fades or the memory device is erased by applying a voltage.

The first terminals with storage tubes were ARDS terminal of computer displays and the 400 series of Computek, both of which were introduced around 1968. They used the 6 × 8 inch Tektronix 611 storage tube, costing 12,000 to 15,000 U.S. dollars. Then brought to the Tektronix 9000 -dollar T4002A, followed by the 4000 -dollar 4010, own terminals out. With the introduction of the 4010 Tektronix dominated the market for storage tubes and thus a large part of computer graphics market. DVSTs enabled tens of thousands of users access to computer graphics, as in previous graphic display terminal is already the hardware had cost 50,000 to 200,000 dollars.