SUPER-SENSITIVE HDTV CAMERA TUBE WITH THE NEWLY DEVELOPED HARP TARGET.

Conventional HDTV cameras lack sensitivity, so the iris must be opened two to three stops wider compared with practical cameras working within existing TV standards. This narrows the depth of focus, sacrificing picture quality. A more sensitive HDTV camera tube that combines a new high-gain avalanche rushing amorphous photoconductor (HARP) target and 2/3-in. high-performance magnetic-focus electrostatic-deflection (MS) electron optics is proposed. The combination results in a super-sensitive camera tube (10 times as sensitive as the Saticon) with an amplitude response of 36 percent at 800 TV lines (aspect ratio 4:3). This was achieved with no sacrifice in picture quality and no deterioration in resolution, lag, spectral response, or noise characteristics. After-image is negligible.