Photocathode capable of detecting position of incident light in one or two dimensions, phototube, and photodetecting apparatus containing same

A phototube comprising:

• a vacuum vessel;
• a photocathode for emitting electrons in response to light input thereto, said photocathode being disposed in said vacuum vessel, wherein said photocathode comprises:
• a semiconductor layer having a first surface and a second surface facing said first surface, wherein the light is incident on said second surface and the electrons are emitted from said first surface,
• a first pixel electrode being a single solid unitary member and having a plurality of openings therein, said first pixel electrode contacting said first surface of said semiconductor layer,
• a first wire electrically connected to said first pixel electrode,
• a second pixel electrode being a single solid unitary member and having a plurality of openings therein, said second pixel electrode being in contact with said first surface of said semiconductor layer, wherein said first pixel electrode and said second pixel electrode are physically isolated from each other,
• a second wire electrically connected to said second pixel electrode, and
• a second surface electrode being in contact with said second surface of said semiconductor laser, wherein said second surface electrode is alternatively electrically connected to one of said first and second wires;
• and
• an anode for receiving the electrons emitted from said photocathode, said anode being disposed in said vacuum vessel.

A photodetecting apparatus comprising:

• a vacuum vessel;
• a photocathode for emitting electrons in response to light included thereon, said photocathode being disposed in said vacuum vessel, wherein said photocathode comprises:
• a semiconductor layer having a first surface and a second surface facing said first surface, wherein the light is incident on said second surface and the electrons are emitted from said first surface,
• a first pixel electrode being a single unitary solid member and having a plurality of openings therein, said first pixel electrode contacting said first surface of said semiconductor layer,
• a first wire electrically connected to said first pixel electrode,
• a second pixel electrode being a single unitary solid member and having a plurality of openings therein, said second pixel electrode contacting said first surface of said semiconductor layer, wherein said first pixel electrode and said second pixel electrode are physically isolated from each other,
• a second wire electrically connected to said second pixel electrode, and
• a second surface electrode contacting said second surface of said semiconductor;
• and
• an anode for receiving the electrons emitted from said photocathode, said anode being disposed in said vacuum vessel;
• a switching element for alternatively electrically connecting said second surface electrode to one of said first and second wires;
• a switching circuit for sequentially switching ON/OFF states of said switching element in response to a timing pulse;
• timing control means for continuously applying said timing pulse to said switching circuit in response to a start signal;
• and
• memory means for beginning to store output from said anode, which collects the electrons emitted from the photocathode, in response to said start signal.