Picture tube with video output, picture taking system utilizing such tube and operating process of said tube
AssigneeThomson-CSF
InventorLucien Guyot
Life of this patent
Estimating the term…
Abstract
A picture tube designed for providing an electrical output includes a vacuum enclosure provided with a window transparent to the radiation to be converted to an electrical signal and a window transparent to a scanning light beam. The enclosure houses an assembly including a screen and a photocathode having a mosaic of picture storage elements, and an electron-emissive cathode for establishing a reference potential on the photocathode, an anode for collecting signal electrons, a field grid and electron optics. An external light source is used to provide a light beam for scanning the photocathode.
Claims20
A picture tube with video output for transforming incident radiation into an electrical signal comprising
- a vacuum enclosure including an entrance window transparent to the radiation and an entrance window transparent to a light beam,
- an assembly including a screen and a photocathode forming a mosaic of picture storage elements positioned to intercept the radiation passing into the enclosure for converting it into a stream of emitted electrons and for storing the pattern of the incident radiation,
- means for setting the maximum potential of the photocathode and for provoking the emission of the electrons,
- means for establishing a reference potential on the photocathode by electron bombardment,
- means for providing a light beam for scanning the photocathode and for establishing said maximum potential on the photocathode by the photoemission of electrons, and
- means for collecting the video output signal formed during the scanning of the photocathode, and electron optics for controlling the flow of the different streams of electrons.
The process of operating a picture tube with video output for transforming incident radiation into an electrical signal comprising
- a vacuum enclosure including an entrance window transparent to the radiation and an entrance window transparent to a light beam,
- an assembly including a screen and a photocathode forming a mosaic of picture storage elements positioned to intercept the radiation passing into the enclosure for converting it into a stream of emitted electrons and for storing the pattern of the incident radiation,
- means for setting the maximum potential of the photocathode and for provoking the emission of the electrons,
- means for establishing a reference potential on the photocathode by electron bombardment,
- means for providing a light beam for scanning the photocathode and for establishing said maximum potential on the photocathode by the photoemission of electrons, and
- comprising irradicating the assembly of screen and photocathode with the radiation to be detected for converting the incident radiation and establishing a potential pattern on the photocathode corresponding to the radiation pattern by the photoemission of electrons,
- scanning the photocathode with a light beam to restore the photocathode to the maximum potential and causing the photoemission of electrons for creating the video output signal, and bombarding the photocathode with electrons to establish the reference potential on the photocathode for resetting.
Dependencies are inferred from the claim text.