X-ray image pickup tube

An X-ray image pickup tube for converting a transmitted X-ray image into electric signals, comprising:

• a fluorescent element for receiving transmitted X-rays in a two-dimensional distribution and converting said transmitted X-rays into visible rays in a two-dimensional distribution;
• a translucent conductive film optically coupled to a surface of said fluorescent element opposite from an X-ray incident surface thereof, said translucent conductive film receiving a high voltage:
• a photoconductive film laminated on said translucent conductive film and including an amorphous semiconductor layer having functions to convert said visible rays transmitted in a two-dimensional distribution through said translucent conductive film, into electric charges in a two-dimensional distribution, and to multiply said electric charges in the two-dimensional distribution based on electric fields formed by said high voltage applied to said translucent conductive film;
• and
• signal reading means for scanning a surface of said photoconductive film Opposite from a visible ray incident surface thereof to read, as electric signals, a two-dimensional electric potential distribution occurring on said photoconductive film,
• wherein said signal reading means comprises a group of switching elements arranged two-dimensionally on said photoconductive film.

An X-ray image pickup tube for converting a transmitted X-ray image into electric Signals, comprising:

• a fluorescent element for receiving transmitted X-rays in a two-dimensional distribution and converting said transmitted X-rays into visible rays in a two-dimensional distribution:
• a translucent conductive film optically coupled to a surface of said fluorescent element opposite from an X-ray incident surface thereof, said translucent conductive film receiving a high voltage;
• a photoconductive film laminated on said translucent conductive film and including an amorphous semiconductor layer having functions to convert said visible rays transmitted in a two-dimensional distribution through said translucent conductive film, into electric charges in a two-dimensional distribution, and to multiply said electric charges in the two,dimensional distribution based on electric fields formed by said high voltage applied to said translucent conductive film:
• and
• signal reading means for scanning a surface of said photoconductive film opposite from a visible ray incident surface thereof to read, as electric signals, a two-dimensional electric potential distribution occurring on said photoconductive film,
• wherein said signal reading means comprises an electron beam generating mechanism including:
• a plurality of linear cathodes acting as electron beam sources juxtaposed opposite a surface of said fluorescent element in a target structure including said fluorescent element, said translucent conductive film and said photoconductive film;
• a plurality of backing electrodes arranged rearwardly of said linear cathodes (i.e. at a side remote from said target structure) and in corresponding relations with said linear cathodes, respectively;
• a plurality of vertically converging electrodes arranged forwardly of and in corresponding relations with said linear cathodes (i.e. at a side opposed to said target structure) for producing potential gradients with said backing electrodes, thereby to allow only a selected one of said linear cathodes to generate an electron beam, and to converge vertically and thrust said electron beam forward;
• a plurality of vertically deflecting electrodes arranged in corresponding relations with said linear cathodes for vertically deflecting electron beams having passed through said vertically converging electrodes;
• a plurality of electron beam flow control electrodes for acting on the electron beams having passed through said vertically deflecting electrodes to switch paths of said electron beam successively along a horizontal line;
• a plurality of horizontally deflecting electrodes associated with said electron beam flow control electrodes for horizontally deflecting the electron beams having passed through said electron beam flow control electrodes;
• a plurality of accelerating electrodes for drawing the electron beam having passed through said horizontally deflecting electrodes toward said target structure;
• and
• a decelerating electrode for decelerating the electron beam having passed through said accelerating electrodes before said target structure.