Abstract: An image converter is disclosed which can be operated by means of a relatively low voltage D.C. supply. In this invention, the luminescent screen of the image converter is brought closer to the photocathode by forming the exit window with a frustrum-shaped platform with a top surface that is parallel to the entrance window, and upon which top surface the luminescent screen is mounted. As a result of the closer spacing between the photocathode and the luminescent screen, lower D.C. supply voltages can be utilized. Moreover, the shape of the housing which supports the two windows at the image converter is so designed that the interior surface of the housing is non-perpendicular to the equipotential lines of the electric field which is established between the photocathode and the luminescent screen. As a result of this geometrical relationship, avalanche discharge is reduced or eliminated altogether, thereby reducing or eliminating the undesirable arcing which can occur as a result of such avalanche discharge.

Abstract: In order to increase the sensitivity of television cameras so as to allow the cameras to operate in low level light, an image transformer attachment, in the form of an ancillary image intensifier, is provided for attachment to the objective lens opening of the camera. The attachment includes a cylindrical housing containing one or more proximity-focus image converters or intensifiers which are optically connected to the pick-up tube of the camera by a fiber optics cylindrical block. The housing includes an annular disk screwed into its input end, which disk has an opening for the objective lens of the camera and which disk urges a resilient ring against the image transformers to bias the intensifier and fiber optics block against the pick-up tube of the camera.