Video camera tubes are devices based on the cathode-ray tube that were used in television cameras to capture television images, prior to the introduction of charge-coupled device (CCD) image sensors in the 1980s. Several different types of tubes were in use from the early 1930s, and as late as the 1990s.
In these tubes, an electron beam is scanned across an image of the scene to be broadcast focused on a target. This generated a current that is dependent on the brightness of the image on the target at the scan point. The size of the striking ray is tiny compared to the size of the target, allowing 480–486 horizontal scan lines per image in the NTSC format, 576 lines in PAL,[1] and as many as 1035 lines in Hi-Vision.
- ^ Jack, K.; Tsatsoulin, V. (2002). Dictionary of Video and Television Technology. Amsterdam: Newnes Press. pp. 143, 148. ISBN 978-1-878707-99-4. OCLC 50761489.