Field emission microcathode array and printer including the array

A field emission microcathode array comprising:

• a substrate having a main surface;
• a plurality of cones formed on the main surface of the substrate and arranged in a respective plurality of blocks, each of said blocks comprising a plurality of respective cones and each of said cones having a sharp tip and emitting an electron beam from the sharp tip thereof when induced by field emission;
• a gate electrode comprising a main electrode portion connected to a common power source and a plurality of electrically and structurally independent gate electrode portions respectively corresponding to the plurality of blocks and disposed within the main electrode portion, each of said gate electrode portions being electrically isolated by a surrounding groove from the main electrode portion and from each other said gate electrode portion and having a plurality of openings therein corresponding to the plurality of cones of the respective one of the blocks, each of said openings being aligned with and disposed in surrounding relationship relatively to the corresponding tip of the respectively associated one of the cones;
• and
• a plurality of conductor elements of electrically conductive material, comprising corresponding portions of the gate electrode material, independently electrically connecting the respectively corresponding gate electrode portions to the main electrode portion, each of the plurality of conductor elements being configured as a fuse and providing a current conducting path connecting the respective one of the gate electrode portions to the main electrode portion.

A field emission microcathode array comprising:

• a substrate having a main surface;
• a plurality of cones formed on the main surface of the substrate and arranged in a plurality of blocks, each of said blocks comprising a plurality of respective cones and each of said cones having a sharp tip and emitting an electron beam from the sharp tip thereof when induced by field emission;
• a gate electrode comprising a plurality of electrically and structurally independent gate electrode portions having respective peripheries and respectively corresponding to the plurality of blocks, each of said gate electrode portions having a plurality of openings therein corresponding to the plurality of cones of the respective one of the blocks and each of said openings being aligned with and disposed in surrounding relationship relatively to the corresponding tip of the respectively associated one of the cones, the gate electrode portions being made of an electrically conducting material;
• and
• a wiring portion, comprising an electrically conducting material, disposed around the peripheries of and contacting the gate electrode portions, the wiring portion and the gate electrode portions being made of respective, relatively lower and higher resistance materials.

A field emission microcathode array comprising:

• a substrate over which a plurality of cones is formed, each of said cones having a corresponding sharp tip;
• a gate electrode having a plurality of openings therein, each of said openings surrounding the corresponding tip of a respective cone, the tips of the cones emitting electron beams because of field emission;
• and
• the openings formed on a common gate electrode having respective, different sizes relatively to each other and being intermingled.

A printer having a head and a photoconductor drum, the head comprising:

• a field emission microcathode array comprising:
• a substrate having a main surface,
• a plurality of cones formed on the main surface of the substrate and arranged in a plurality of blocks, each of said blocks comprising a plurality of respective cones and each of said cones having a sharp tip and emitting an electron beam from the sharp tip thereof when induced by field emission,
• a gate electrode comprising a plurality of electrically and structurally independent gate electrode portions respectively corresponding to the plurality of blocks, each of said gate electrode portions having a plurality of openings therein corresponding to the plurality of cones of the respective one of the blocks and each of said openings being aligned with and disposed in surrounding relationship relatively to the corresponding tip of the respectively associated one of the cones, and
• a plurality of lead electrodes respectively connected to the plurality of gate electrode portions, each of said lead electrodes being configured as a fuse and providing an independent connection of the respective one of the gate electrode portions to a common power source;
• a fluorescent dot array disposed in facing relationship with respect to the field emission microcathode array, the field emission microcathode array emitting electron beams for selectively irradiating the dots of the fluorescent dot array thereby to cause each of the selectively irradiated fluorescent dots to emit light;
• and
• the photoconductor drum having a photoconductor layer on which a latent image is formed by the light emitted by each of the irradiated fluorescent dots of the fluorescent dot array.

A printer having a head and a photoconductor drum, the head comprising:

• a field emission microcathode array comprising:
• a substrate having a main surface,
• a plurality of cones formed on the main surface of the substrate and arranged in a respective plurality of blocks, each of said blocks comprising a plurality of respective cones and each of said cones having a sharp tip and emitting an electron beam from the sharp tip thereof when induced by field emission,
• a gate electrode comprising a main electrode portion connected to a common power source and a plurality of electrically and structurally independent gate electrode portions respectively corresponding to the plurality of blocks and disposed within the main electrode portion, each of said gate electrode portions being electrically isolated by a surrounding groove from the main electrode portion and from each other of said gate electrode portions and having a plurality of openings therein corresponding to the plurality of cones of the respective one of the blocks, each of said openings being aligned with and disposed in surrounding relationship relatively to the corresponding tip of the respectively associated one of the cones, and
• a plurality of conductor elements of electrically conductive material, comprising corresponding portions of the gate electrode material, independently electrically connecting the respectively corresponding gate electrode portions to the main electrode portion, each of the plurality of conductor elements being configured as a fuse and providing a current conducting path connecting the respective one of the gate electrode portions to the main electrode portion;
• a fluorescent dot array disposed in facing relationship with respect to the field emission microcathode array, the field emission microcathode array emitting electron beams for selectively irradiating the dots of the fluorescent dot array thereby to cause each of the selectively irradiated fluorescent dots to emit light;
• and
• the photoconductor drum having a photoconductor layer on which a latent image is formed by the light emitted by each of the irradiated fluorescent dots of the fluorescent dot array.

A printer having a head and a photoconductor drum, the head comprising:

• a field emission microcathode array comprising:
• a substrate having a main surface,
• a plurality of cones formed on the main surface of the substrate and arranged in a plurality of blocks, each of said blocks comprising a plurality of respective cones and each of said cones having a sharp tip and emitting an electron beam from the sharp tip thereof when induced by field emission,
• a gate electrode comprising a plurality of electrically and structurally independent gate electrode portions having respective peripheries and respectively corresponding to the plurality of blocks, each of said gate electrode portions having a plurality of openings therein corresponding to the plurality of cones of the respective one of the blocks and each of said openings being aligned with and disposed in surrounding relationship relatively to the corresponding tip of the respectively associated one of the cones, the gate electrode portions being made of an electrically conducting material, and
• a wiring portion, comprising an electrically conducting material, disposed around the peripheries of and contacting the gate electrode portions, the wiring portion and the gate electrode portions being made of respective, relatively lower and higher resistance materials;
• a fluorescent dot array disposed in facing relationship with respect to the field emission microcathode array, the field emission microcathode array emitting electron beams for selectively irradiating the dots of the fluorescent dot array thereby to cause each of the selectively irradiated fluorescent dots to emit light;
• and
• the photoconductor drum having a photoconductor layer on which a latent image is formed by the light emitted by each of the irradiated fluorescent dots of the fluorescent dot array.

A printer having a head and a photoconductor drum, the head comprising:

• a field emission microcathode array comprising:
• a substrate over which a plurality of cones is formed, each of said cones having a corresponding sharp tip,
• a gate electrode having a plurality of openings therein, each of said openings surrounding the corresponding tip of a respective cone, the tips of the cones emitting electron beams because of field emission, and
• the openings formed on a common gate electrode having respective, different sizes relatively to each other and being intermingled;
• a fluorescent dot array disposed in facing relationship with respect to the field emission microcathode array, the field emission microcathode array emitting electron beams for selectively irradiating the dots of the fluorescent dot array thereby to cause each of the selectively irradiated fluorescent dots to emit light;
• and
• the photoconductor drum having a photoconductor layer on which a latent image is formed by the light emitted by each of the irradiated fluorescent dots of the fluorescent dot array.