DIRECT VIEW STORAGE TUBE

DIRECT VIEW STORAGE TUBE

D V S T is used today as part of a display system. DVST marks a technology change in usual refresh type display. Both in raster scan & random scan system the screen image is maintained by redrawing or refreshing the screen many lines. The DVST give the alternative method of maintaining the screen image. DVST use the storage grid which stores the picture information as a charge distribution just behind the phosphor-coated screen. In DVST there is no refresh buffer the images are created by drawing vector and line segments with a slow-moving electron beam. It consists of 2 electron guns, a primary gun and a flood gun. A primary gun stores the pictures pattern and the flood guns maintain the picture display. A primary gun produces high speed electron which stripe on the storage grid to draw the picture pattern. As electron beam strikes on the storage grid with high speeds It knocked out the electron from the storage grid keeping the not positive change. The knocked-out electron are attached the collector. The net positive charge on the storage grid is nothing but picture pattern. The continuous low speed electron from flood gun pass through the control grid and are attached to the positive charged areas of the storage grid. The low speed electron then penetrates the storage grid and strike the phosphor the collector just behind the storage grid smooth out the flow of flood electron.

ADVANTAGES:
1. It has flat screen.
2. Refreshing of screen is not required.
3. Because no refreshing is required, very complex pictures can be displayed.
4. DVST is much cheaper than random scan display. 5. Very advanced image may be displayed at very high resolution without flicker.

DISADVANTAGES:
1.They does not display colors.
2. Selecting or part erasing of screen is not possible.